Functionalised benzopyran compounds and use thereof

ABSTRACT

Benzopyran compounds, the preparation thereof, and their use in methods for treating cancer and reducing the incidence or risk of cancer recurrence. The cancer can be one or more of pancreatic cancer, colorectal cancer, melanoma, prostate cancer, brain cancer (including paediatric and adult), ovarian cancer, breast cancer, lung cancer, liver cancer, uterine cancer, neuroblastoma, mesothelioma, malignant ascites or peritoneal cancer.

PRIORITY CLAIM

This application is a continuation of U.S. application Ser. No.14/771,440 filed Aug. 28, 2015, which is a National Stage ofInternational Application No. PCT/AU2015/050040 filed Feb. 5, 2015,which claims priority to Provisional Patent Application No. 61/937,368filed Feb. 7, 2014 and Provisional Patent Application No. 61/987,323filed May 1, 2014, the entire contents of which are incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates broadly to anti-cancer agents. Inparticular, the present invention relates to selected benzopyrancompounds, the preparation thereof, and their use in methods fortreating cancer and reducing the incidence or risk of cancer recurrence.

BACKGROUND OF THE INVENTION

Cancer kills many thousands of people annually throughout the world.There have been significant breakthroughs made in the treatment andprevention of a wide variety of cancers. For example breast cancer hasseen early screening programs as well as a variety of surgicaltechniques. However, these often prove physically and emotionallydebilitating. Moreover, patients who have undergone surgery andsubsequent chemotherapy often experience a recurrence. In recent yearsresearch has indicated the heterogeneous tumorigenic potential of cancercells which has lead to the cancer stem cell (CSC) hypothesis. In brief,this hypothesis states that only a fraction of cells within a tumor havestem cell like features, including unlimited proliferative potential.

Further evidence in the literature supports the concept that tumours arecomplex heterogeneous organ-like systems with a hierarchical cellularorganization, rather than simply as collections of homogeneous singlelineage tumour cells. The initiator tumour cell retains the capacity togenerate diverse progeny at various levels of differentiation, fromuncommitted pluripotent stem cells, to committed progenitor cells, tofully differentiated senescent descendent cells. In this way, the tumourcell population itself is heterogeneous, adding diverse architectureafforded by the immune, stromal, and vascular cells that are alsopresent in tumours. Some of the cells within this “cancer organ” ortumour have the potential for continued proliferation. The phylogeny ofthese tumor cells thus suggests the existence of a cell population thatretains the ability to self-renew while also often possessing thecapacity to generate progeny that differentiate. Hence, the cancer stemcell is defined as being a cell within a tumour that possesses thecapacity to self-renew and to cause the heterogeneous lineages of cancercells that comprise the tumour. Indeed laboratory evidence confirms thatinjection of isolated ovarian, brain, colon, breast, prostate orpancreatic cancer stem-like cells into immunocompromised mice results inthe formation of tumours that are phenotypically identical to theoriginal tumour and contain both stem-like cells and non-stem-likecells. Hence there are two distinct populations; a relativelywell-differentiated subset with limited proliferative capacity formingthe bulk of the tumor which phenotypically characterises the disease,and a second smaller, less differentiated subset that containsclonogenic CSCs. Importantly CSCs exhibit multiple-drug resistance, anadditional property that contributes to their longevity and metastaticpotential by permitting them to survive toxic insults, including many ofthe drugs currently used to treat cancer. There is therefore a need todevelop therapies that specifically target the self-renewal capabilitiesof the stem cell population, thereby abrogating the source of tumourrecurrence as a result of resistance to conventional therapies.

Putative CSC markers that have been described for other malignancies,including acute myeloid leukemia (CD34-positive/CD38-negative), breast(CD44-positive/CD24-negative/-low/Linnegative), prostate(CD44-positive/_2_1-high/CD133-positive) and brain(CD133-positive/nestinpositive), have reflected those expressed by theirnormal tissue counterparts' original status. Recent evidence confirmsthat CD44+ ovarian cancer cells also possess the ability to form tumoursin immunocompromised mice. As with other CSC phenotypes, ovarian cancerstem cells are slow growing, chemoresistant and form tumours inimmunocompromised mice that are phenotypically identical to the originaltumour in that there are mainly CD44−ve cells forming the bulk of thetumour with small pockets of CD44+ve cells.

Many advanced cancers recur despite the use of chemotherapeutic andradiation modalities that initially lead to therapeutic responses. Forexample, irradiation of glioblastomas can lead to significantradiographic responses, yet these tumors invariably recur and lead topatient death. Frequently, glioblastomas recur in a nodular pattern,suggesting a clonal or polyclonal source of recurrent tumor cells thatare able to withstand conventional cytotoxic therapies, includingradiation therapy, to cause recurrence of disease. Furthermore,recurrent tumors also demonstrate heterogeneity within the tumor cellpopulation with regard to the presence of both CSCs and non-CSCs as wellas in histologic and cytogenetic differences. This suggests that theCSCs that populated the original tumor may have withstood therapeuticintervention to repopulate the recurrent tumor even after the bulk ofthe tumor had been removed by resection or chemoradiation therapy, hencethe concept that CSCs are the source of post-therapeutic tumourrecurrence. A shift in therapeutic strategy that leads to thedevelopment of unique targeted agents that attack CSCs may enhancecancer care and prolong the survival of many patients.

The present inventors have surprisingly discovered that a selection ofbenzopyran compounds are able to exert powerful biological effects onnon-CSCs as well as CSCs. Such compounds offer alternativechemotherapeutic strategies for treating cancer and reducing theincidence or risk of cancer recurrence.

SUMMARY OF THE INVENTION

In a first aspect the present invention provides a compound of thegeneral formula (I)

or a pharmaceutically acceptable salt, hydrate, derivative, solvate orprodrug thereof, wherein:

R¹ is selected from the group consisting of: H and C₁-C₆ alkyl,

R² is selected from the group consisting of: OH and C₁-C₆ alkoxy,

R³ is selected from the group consisting of: H, C₁-C₆ alkyl and halo,

R¹⁰ to R¹² are independently selected from the group consisting of: OH,C₁-C₆ alkyl, C₁-C₆ alkoxy and halo,

R¹³ is selected from the group consisting of: OH, C₁-C₆ alkoxy, NH₂,NHMe, NHEt, N(Me)₂ and N(Et)₂,

R¹⁴ and R¹⁵ are independently selected from the group consisting of: H,OH, C₁-C₆ alkyl and halo, or

R¹³ and one of R¹⁴ and R¹⁵ together form the following structure:

In a second aspect the present invention provides a pharmaceuticalcomposition comprising a compound of formula (I) according to the firstaspect together with a pharmaceutically acceptable carrier, diluent orexcipient.

In a third aspect the present invention provides a method for thetreatment of cancer in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount of acompound of formula (I) according to the first aspect, or a compositionof the second aspect.

The method may further comprise administration of anotherchemotherapeutic agent.

The cancer may be a cancer that has recurred.

The cancer may be resistant to one or more chemotherapeutic agents.

The cancer may be pancreatic cancer, colorectal cancer, melanoma,prostate cancer, brain cancer (including paediatric and adult), ovariancancer, breast cancer, lung cancer, liver cancer, uterine cancer,neuroblastoma, mesothelioma, malignant ascites or peritoneal cancer.

In a fourth aspect the present invention provides use of a compound offormula (I) according to the first aspect in the manufacture of amedicament for treating cancer.

The medicament may further comprise, or may be administered with,another chemotherapeutic agent.

In a fifth aspect the present invention provides a compound of formula(I) according to the first aspect for use in the treatment of cancer.

In a sixth aspect the present invention provides a method for reducingincidences of, or risk of, cancer recurrence in a subject deemed to beat risk of cancer recurrence, the method comprising administration tothe subject of an effective amount of a compound of formula (I)according to the first aspect, or a composition of the second aspect.

The subject may be a subject who is in cancer remission. The subject maybe in remission from ovarian cancer, brain cancer or some other cancersuch as one or more of those recited above.

In a seventh aspect the present invention provides use of a compound offormula (I) according to the first aspect in the manufacture of amedicament for reducing incidences of, or risk of, cancer recurrence ina subject deemed to be at risk of cancer recurrence.

In an eighth aspect the present invention provides a compound of formula(I) according to the first aspect for use in reducing incidences of, orrisk of, cancer recurrence in a subject deemed to be at risk of cancerrecurrence.

In a ninth aspect the present invention provides a method for inducingapoptosis in, or inhibiting the proliferation of, a cancer stem cell,the method comprising contacting the cancer stem cell with an effectiveamount of a compound of formula (I) according to the first aspect.

The cancer stem cell may be an ovarian cancer stem cell or a braincancer stem cell.

In a tenth aspect the present invention provides use of a compound offormula (I) according to the first aspect in the manufacture of amedicament for inducing apoptosis in, or inhibiting the proliferationof, a cancer stem cell.

In an eleventh aspect the present invention provides a method fortreating a disease in a subject caused by cancer stem cells, the methodcomprising administration to the subject of a therapeutically effectiveamount of a compound of the formula (I) according to the first aspect,or a composition of the second aspect.

The disease may be cancer. The cancer may be a metastatic cancer. Thecancer stem cells may be ovarian cancer stem cells or brain cancer stemcells.

In a twelfth aspect the present invention provides use of a compound ofthe formula (I) according to the first aspect in the manufacture of amedicament for treating a disease caused by cancer stem cells.

In a thirteenth aspect the present invention provides a compound of theformula (I) according to the first aspect for use in treating a diseasecaused by cancer stem cells.

In a fourteenth aspect the present invention provides a method forpreparing a compound of the formula (I) comprising the steps of:

(a) reducing a compound of formula (II) to produce a compound of formula(III):

wherein in the compound of formula (II) R¹, R³, and R¹⁰ to R¹⁵ are asdefined in the first aspect, and R² is OAc or as defined in the firstaspect, and in the compound of formula (III) R¹ to R³ and R¹⁰ to R¹⁵ areas defined in the first aspect, and

(b) hydrogenating a compound of formula (III) to produce a compound offormula (I),

wherein R¹ to R³, and R¹⁰ to R¹⁵ are as defined in the first aspect.

Step (a) may be carried out by reacting a compound of formula (II) witha borane reagent, for example borane dimethylsulfide complex, decborane,9-BBN or borane tetrahydrofuran complex.

Step (b) may be carried out by reacting a compound of formula (III) witha heterogenous metal catalyst with a heterogenous metal catalyst underan atmosphere of hydrogen.

In one embodiment the method may further comprise:

(c) reacting a compound of formula (IV) with a compound of formula (V)to produce a compound of formula (II)

wherein in the compound of formula (II) R¹, R³, and R¹⁰ to R¹⁵ are asdefined in the first aspect, and R² is OAc or as defined in the firstaspect, and in the compound of formula (IV) R¹ to R³ and R¹³ to R¹⁵ areas defined in the first aspect, and in the compound of formula (V) R¹⁰to R¹² are as defined in the first aspect.

Step (c) may be carried out in the presence of a base.

In another embodiment the method may further comprise:

(d) reacting a compound of formula (VI) with a compound of formula (VII)to produce a compound of the formula (IV)

wherein R¹ to R³, and R¹³ to R¹⁵ are as defined in the first aspect.

Step (d) may be carried out by combining compounds (VI) and (VII) in thepresence of phosphorous oxychloride and zinc chloride. In an alternativeembodiment step (d) may be carried out by reacting compound (VII) withthionyl chloride, followed by reaction with aluminium chloride andcompound (VI).

Definitions

The following are some definitions that may be helpful in understandingthe description of the present invention. These are intended as generaldefinitions and should in no way limit the scope of the presentinvention to those terms alone, but are put forth for a betterunderstanding of the following description.

Throughout this specification, unless the context requires otherwise,the word “comprise”, or variations such as “comprises” or “comprising”,will be understood to imply the inclusion of a stated element, integeror step, or group of elements, integers or steps, but not the exclusionof any other element, integer or step, or group of elements, integers orsteps.

The terms “a” and “an” are used herein to refer to one or to more thanone (i.e. to at least one) of the grammatical object of the article. Byway of example, “an element” means one element or more than one element.

In the context of this specification, the term “alkyl” is taken to meanstraight chain or branched chain monovalent saturated hydrocarbon groupshaving the recited number of carbon atoms. Examples of alkyl groupsinclude, but are not limited to, methyl, ethyl, 1-propyl, isopropyl,1-butyl, 2-butyl, isobutyl, tert-butyl, amyl, 1,2-dimethylpropyl,1,1-dimethylpropyl, pentyl, isopentyl, hexyl, 4-methylpentyl,1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl,3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl, 2-ethylpentyl,3-ethylpentyl, heptyl, 1-methylhexyl, 2,2-dimethylpentyl,3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl,1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl,1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, 5-methylheptyl,1-methylheptyl, octyl, nonyl and decyl.

In the context of this specification, the term “alkoxy” is taken to mean0-alkyl groups in which alkyl is as defined herein. Examples of alkoxygroups include, but are not limited to, methoxy, ethoxy, n-propoxy,isopropoxy, sec-butoxy and tert-butoxy.

In the context of this specification, the term “prodrug” means acompound which is able to be converted in vivo by metabolic means (e.g.by hydrolysis, reduction or oxidation) to a compound of the formula (I).For example, an ester prodrug of a compound of the formula (I)containing a hydroxy group may be hydrolysed in vivo to the parentmolecule. Suitable esters are, for example, acetates, citrates,lactates, tartrates, malonates, oxalates, salicylates, propionates,succinates, fumarates and maleates.

In the context of this specification, the term “effective amount”includes a non-toxic but sufficient amount of an active compound toprovide the stated effect. When used in reference to cancer recurrence“effective amount” means an amount of a compound of formula (I) that isrequired to reduce the incidence of, or risk of an individualexperiencing cancer recurrence. Those skilled in the art will appreciatethat the exact amount of a compound required will vary based on a numberof factors and thus it is not possible to specify an exact “effectiveamount”. However, for any given case an appropriate “effective amount”may be determined by one of ordinary skill in the art.

In the context of this specification, the term “therapeuticallyeffective amount” includes a non-toxic but sufficient amount of anactive compound to provide the desired therapeutic effect. Those skilledin the art will appreciate that the exact amount of a compound requiredwill vary based on a number of factors and thus it is not possible tospecify an exact “therapeutically effective amount”. However, for anygiven case an appropriate “therapeutically effective amount” may bedetermined by one of ordinary skill in the art.

In the context of this specification, the terms “treating”, “treatment”,“preventing” and “prevention” refer to any and all uses which remedycancer or symptoms thereof, prevent the establishment of cancer, orotherwise prevent, hinder, retard or reverse the progression of canceror other undesirable symptoms in any way whatsoever. Thus, the terms“treating”, “treatment”, “preventing” and “prevention” and the like areto be considered in their broadest context. For example, treatment doesnot necessarily imply that a subject is treated until total recovery.

In the context of this specification, the term “subject” includes humanand also non-human animals. As such, in addition to being useful in thetreatment of cancer in humans, the compounds of the present inventionalso find use in the treatment of cancer in non-human animals, forexample mammals such as companion animals and farm animals. Non-limitingexamples of companion animals and farm animals include dogs, cats,horses, cows, sheep and pigs. Preferably, the subject is a human.

In the context of this specification the term “recurrence” as it relatesto cancer is understood to mean the return of cancerous cells and/or acancerous tumour after cancerous cells and/or a cancerous tumour havebeen successfully treated previously.

In the context of this specification the term “administering” andvariations of that term including “administer” and “administration”,includes contacting, applying, delivering or providing a compound orcomposition of the invention to an organism by any appropriate means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Differential activity of compound 2 against two different GBMpatient-derived explants; GBM14-CHA (diamonds) and ODA14-RAV (squares).

FIG. 2: Differential activity of compound 2 and its purified enantiomersagainst the GBM14 GBM patient-derived explant.

FIG. 3: Analysis of the efficacy of compound 2 against OCSC-2 cellsusing confluence (A, B), and cell damage (C, D) imaging. The IC₅₀ wascalculated from plots of AUC for confluence and fluorescence intensityagainst time. IC₅₀ calculations were conducted after 72 hrs culture.

FIG. 4: Analysis of the efficacy of compound 2 against OCSC-2 cellsusing confluence. IC₅₀ calculations were conducted after 72 hrs culture.GAD 305 is compound 9 herein and GAD 310 is compound 13 herein.

FIG. 5: Assessment of the racemate of compound 2 (A, C) and its eutomer(B, D) against the A172 (Glioma) (A and B) and OVCAR-3 (ovarian cancer)(C and D) cell lines.

FIG. 6: Ability of compound 2 to retard the proliferation of ovariancancer stem cells.

FIG. 7: Microscopic evaluation of OCSC2 cells treated with compound 2 at1 μg/ml over 24 (B) and 48 hrs (C) compared with control, 72 hrs (A).

FIG. 8: Fluorescent microscopy of GFP-labeled OCSC-2 stem cells andmCherry-labeled OCC2 co-cultures treated with compound 2 at 1 μg/ml over48 hrs (B) compared with control (A).

FIG. 9: Compound 2 destroys ovarian cancer stem cell spheroids. OCSC-2spheroids were established using standard methodology and exposed toincreasing concentration of compound 2 over 24 hrs. A, Control; B, 0.1μg/ml—24 hr; C, 1 μg/ml—24 hr Spheroid structure was assessed bymicroscopy.

FIG. 10: PK profile of compounds 2, 6, 9 and 13 (which is labelled as31) at 1 mg/kg delivered in 30% Captisol® formulation.

FIG. 11: In vivo efficacy of compound 9 eutomer against a flank model ofGBM (U87MG). Using the U87 flank model previously described, mice weredivided into two groups, a treatment group (compound 9 eutomer)formulated in a cocoa-butter suppository base and dosed daily at 100mg/kg—and a suppository control group (n=10 for control and n=4 forcompound 9). Mice were observed daily, weighed every third day andeuthanized after 12 days of treatment. On termination of the treatment,tumours were excised and weighed. Compound 9 was administered daily at100 mg/kg in a suppository formulation while control animals were dosedwith the suppository formulation only. Tumour growth curves (mean±SEM)for the extent of treatment (12 days) were significantly different (Pvalues shown). Tumour weight (median and quartiles) was alsosignificantly reduced (P values shown above graph).

FIG. 12: In vivo efficacy of compound 2 eutomer in an ovarian canceranimal model. Animals were inoculated with OCSC1-F2 m-Cherry cells andthen dosed on day 4 post-inoculation with Captisol® formulated compound2 eutomer using two different regimens (100 mg/kg, i.p., qd, 50 mg/kg,i.p.) and efficacy compared with control. A, Average tumor fluorescenceintensity (tumors were visualized every third day using a Vivo FXImaging system, ROI) ●, Captisol® control; ▪, compound 2 eutomer (50mg/kg i.p. daily); ▴, compound 2 eutomer (100 mg/kg i.p. daily); B,Average terminal tumor burden was assessed by removing and weighing alltumors from both the control and Captisol® formulated compound 2 eutomertreated animals, *, p<0.02; **, p<0.0001; vs respective controls.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to selected benzopyran compounds of thegeneral formula (I), the preparation of such compounds and their use intreating cancer and reducing the incidence of cancer recurrence. Thecompounds disclosed herein represent a selection invention with respectto US2012/0251630 and WO2012/061409.

In one aspect the present invention provides a compound of the generalformula (I)

or a pharmaceutically acceptable salt, hydrate, derivative, solvate orprodrug thereof, wherein:

R¹ is selected from the group consisting of: H and C₁-C₆ alkyl,

R² is selected from the group consisting of: OH and C₁-C₆ alkoxy,

R³ is selected from the group consisting of: H, C₁-C₆ alkyl and halo,

R¹⁰ to R¹² are independently selected from the group consisting of: OH,C₁-C₆ alkyl, C₁-C₆ alkoxy and halo,

R¹³ is selected from the group consisting of: OH, C₁-C₆ alkoxy, NH₂,NHMe, NHEt, N(Me)₂ and N(Et)₂,

R¹⁴ and R¹⁵ are independently selected from the group consisting of: H,OH, C₁-C₆ alkyl and halo, or

R¹³ and one of R¹⁴ and R¹⁵ together form the following structure:

In one embodiment R¹ is selected from the group consisting of: H andC₁-C₃ alkyl.

In another embodiment R² is OH or OMe. In a further embodiment R² is OH.

In yet another embodiment R³ is selected from the group consisting of:H, C₁-C₃ alkyl and halo. In a further embodiment R³ is selected from thegroup consisting of: H, C₁-C₃ alkyl, F and Cl.

In still a further embodiment R¹⁰ is selected from the group consistingof: OH, OMe and halo. In another embodiment R¹⁰ is selected from thegroup consisting of: OH, OMe, F and Cl. In yet another embodiment R¹⁰ isselected from the group consisting of: OH, OMe and F.

In a further embodiment R¹¹ and R¹² are independently selected from thegroup consisting of: OH, OMe, C₁-C₄ alkyl and F. In yet anotherembodiment R¹¹ and R¹² are independently selected from the groupconsisting of: OH, OMe, methyl, tert-butyl and F. In still a furtherembodiment R¹¹ and R¹² are independently selected from the groupconsisting of: OMe, methyl, tert-butyl and F. In yet another embodimentR¹¹ and R¹² are independently selected from the group consisting of: OH,OMe, tert-butyl and F. In still a further embodiment R¹¹ and R¹² areindependently selected from the group consisting of: OMe, tert-butyl andF.

In another embodiment R¹³ is selected from the group consisting of: OH,OMe, NH₂, NHEt and N(Et)₂.

In a further embodiment R¹⁴ and R¹⁵ are independently selected from thegroup consisting of: H, F, Cl and methyl.

In still a further embodiment R¹³ and one of R¹⁴ and R¹⁵ form thefollowing structure:

In one embodiment the compounds of formula (I) have the followingstructure

wherein R¹, R³ and R¹⁰ to R¹⁵ are as defined above.

In one embodiment R¹ is selected from the group consisting of: H andC₁-C₆ alkyl. In another embodiment R¹ is selected from the groupconsisting of: H and C₁-C₃ alkyl

In a further embodiment R³ is selected from the group consisting of: H,C₁-C₆ alkyl and halo. In a further embodiment R³ is selected from thegroup consisting of: H, C₁-C₃ alkyl, F and Cl.

In another embodiment R¹⁰ is selected from the group consisting of: OH,OMe and halo. In still a further embodiment R¹⁰ is selected from thegroup consisting of: OH, OMe, F and Cl. In another embodiment R¹⁰ isselected from the group consisting of: OH, OMe and F.

In still a further embodiment R¹¹ is selected from the group consistingof: tert-butyl, OMe, methyl and halo. In yet another embodiment R¹¹ isselected from the group consisting of: tert-butyl, OMe, methyl, F andCl. In yet another embodiment, R¹¹ is selected from the group consistingof: tert-butyl, OMe, methyl and F.

In a further embodiment R¹² is selected from the group consisting of:OMe, tert-butyl, methyl and halo. In yet another embodiment R¹² isselected from the group consisting of: OMe, tert-butyl, methyl, F andCl. In still a further embodiment R¹² is selected from the groupconsisting of: OMe, methyl, tert-butyl and F.

In still a further embodiment R¹¹ is selected from the group consistingof: tert-butyl, OMe, and halo. In yet another embodiment R¹¹ is selectedfrom the group consisting of: tert-butyl, OMe, F and Cl. In yet anotherembodiment, R¹¹ is selected from the group consisting of: tert-butyl,OMe and F.

In a further embodiment R¹² is selected from the group consisting of:OMe, tert-butyl and halo. In yet another embodiment R¹² is selected fromthe group consisting of: OMe, tert-butyl, F and Cl. In still a furtherembodiment R¹² is selected from the group consisting of: OMe, tert-butyland F.

In yet another embodiment R¹³ is selected from the group consisting of:OH, OMe, NH₂, NHEt and NEt₂.

In another embodiment R¹⁴ and R¹⁵ are independently selected from thegroup consisting of: H, halo and methyl. In another embodiment R¹⁴ andR¹⁵ are independently selected from the group consisting of: H, F, Cland methyl.

In still a further embodiment R¹³ and one of R¹⁴ and R¹⁵ form thefollowing structure:

In one embodiment, R¹ is selected from the group consisting of: H andC₁-C₃ alkyl, R³ is selected from the group consisting of: H, C₁-C₃alkyl, F and Cl, R¹⁰ is selected from the group consisting of: OMe, OHand F, R¹¹ and R¹² are independently selected from the group consistingof: tert-butyl, methyl, OMe and F, R¹³ is selected from the groupconsisting of: OMe and OH and R¹⁴ and R¹⁵ are independently selectedfrom the group consisting of: H, F, Cl and methyl.

In another embodiment, R¹ is selected from the group consisting of: Hand C₁-C₃ alkyl, R³ is selected from the group consisting of: H, C₁-C₃alkyl, F and Cl, R¹⁰ is selected from the group consisting of: OMe, OHand F, R¹¹ and R¹² are independently selected from the group consistingof: tert-butyl, methyl, OMe and F, R¹³ is selected from the groupconsisting of: OMe and OH and R¹⁴ and R¹⁵ are independently selectedfrom the group consisting of: H, F, Cl and methyl, or R¹³ and one of R¹⁴and R¹⁵ form the following structure:

In a further embodiment, R¹ and R³ are independently selected from thegroup consisting of: H, methyl or ethyl, R¹⁰ is selected from the groupconsisting of: OMe, OH and F, R¹¹ and R¹² are independently selectedfrom the group consisting of: tert-butyl, methyl, OMe and F, R¹³ isselected from the group consisting of: OMe and OH and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F and methyl. Inthis embodiment R¹⁵ may be ortho or meta to R¹³.

In another embodiment, R¹ and R³ are independently selected from thegroup consisting of: H, methyl or ethyl, R¹⁰ is selected from the groupconsisting of: OMe, OH and F, R¹¹ and R¹² are independently selectedfrom the group consisting of: tert-butyl, methyl, OMe and F, R¹³ isselected from the group consisting of: OMe and OH and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F and methyl, orR¹³ and one of R¹⁴ and R¹⁵ form the following structure:

In one embodiment, R¹ and R³ are independently selected from the groupconsisting of: H, methyl or ethyl, R¹⁰ is selected from the groupconsisting of: OMe, OH and F, R¹¹ and R¹² are independently selectedfrom the group consisting of: tert-butyl, OMe and F, R¹³ is selectedfrom the group consisting of: OMe and OH and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F and methyl. Inthis embodiment R¹⁵ may be ortho to R¹³.

In another embodiment, R¹ and R³ are independently selected from thegroup consisting of: H, methyl or ethyl, R¹⁰ is selected from the groupconsisting of: OMe, OH and F, R¹¹ and R¹² are independently selectedfrom the group consisting of: tert-butyl, OMe and F, R¹³ is selectedfrom the group consisting of: OMe and OH and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F and methyl, orR¹³ and one of R¹⁴ and R¹⁵ form the following structure:

In one embodiment, R¹ is selected from the group consisting of: H andC₁-C₃ alkyl, R³ is selected from the group consisting of: H, C₁-C₃alkyl, F and Cl, R¹⁰ is selected from the group consisting of: OMe, OHand F, R¹¹ and R¹² are independently selected from the group consistingof: tert-butyl, methyl, OMe and F, R¹³ is selected from the groupconsisting of: OMe, OH, NH₂, NHEt and NEt₂ and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F, Cl andmethyl.

In another embodiment, R¹ is selected from the group consisting of: Hand C₁-C₃ alkyl, R³ is selected from the group consisting of: H, C₁-C₃alkyl, F and Cl, R¹⁰ is selected from the group consisting of: OMe, OHand F, R¹¹ and R¹² are independently selected from the group consistingof: tert-butyl, methyl, OMe and F, R¹³ is selected from the groupconsisting of: OMe, OH, NH₂, NHEt and NEt₂ and R¹⁴ and R¹⁵ areindependently selected from the group consisting of: H, F, Cl andmethyl, or R¹³ and one of R¹⁴ and R¹⁵ form the following structure:

Exemplary compounds according to formula (I) include:

In one embodiment the compound of formula (I) is selected from the groupconsisting of: compounds 1 to 14, 16, 18-22, 24 and 32-41. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of: compounds 1 to 14, 16, 18-22, 24 and 32-40. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of: compounds 1 to 14, 16, 18-22, 24 and 32-35. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of: compounds 1 to 14, 16, 18-22, 24 and 32-36. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of: compounds 2, 6, 9, 13, 16, 18-22, 24 and 32-41. Inanother embodiment the compound of formula (I) is selected from thegroup consisting of: compounds 2, 6, 9, 13, 16, 18-22, 24 and 32-40. Ina further embodiment the compound of formula (I) is selected from thegroup consisting of compounds 2, 6, 9, 13, 16, 18-22, 24 and 32-36. In afurther embodiment the compound of formula (I) is selected from thegroup consisting of compounds 2, 6, 9, 13, 16, 18-22, 24 and 32-35. In afurther embodiment the compound of formula (I) is selected fromcompounds 33 and 36 to 41. In a further embodiment the compound offormula (I) is selected from compounds 33, 36, 37 and 39. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of compounds 2, 9 and 36. In another embodiment the compoundof formula (I) is selected from the group consisting of compounds 2, 9,20, 33 and 36. In another embodiment the compound of formula (I) isselected from the group consisting of compounds 2, 9, 33 and 36. Inanother embodiment the compound of formula (I) is selected from thegroup consisting of compounds 2, 6, 9, 13 and 36 to 41. In anotherembodiment the compound of formula (I) is selected from the groupconsisting of compounds 2, 6, 9, 13 and 36 to 40. In another embodimentthe compound of formula (I) is selected from the group consisting ofcompounds 2, 6, 9, 13, 36, 37 and 39. In another embodiment the compoundof formula (I) is compound 2. In another embodiment the compound offormula (I) is compound 9. In another embodiment the compound of formula(I) is compound 36. In alternative embodiments the compound of formula(I) may be any combination of one or more of compounds 1 to 41.

The compounds of formula (I) include at least two chiral centres. Thepresent invention includes all enantiomers and diastereoisomers as wellas mixtures thereof in any proportions. The invention also extends toisolated enantiomers or pairs of enantiomers. Methods of separatingenantiomers and diastereoisomers are well known to persons skilled inthe art. In some embodiments compounds of the formula (I) are racemicmixtures. In other embodiments compounds of the formula (I) are presentin optically pure form.

It will also be recognised by those skilled in the art that in thecompounds of the formula (I) the phenyl substituents attached to theheterocyclic ring can be either cis or trans relative to each other.Preferably, in the compounds of formula (I) these substituents will becis relative to each other. Alternatively, in the compounds of formula(I) these substituents may be trans relative to each other.

In some embodiments compounds of the formula (I) including compounds 1to 41 have the following structure:

In other embodiments compounds of the formula (I) including compounds 1to 41 have the following structure:

Compounds of the formula (I) are also taken to include hydrates andsolvates. Solvates are complexes formed by association of molecules of asolvent with a compound of the formula (I). In the case of compounds ofthe formula (I) that are solids, it will be understood by those skilledin the art that such compounds may exist in different crystalline orpolymorphic forms, all of which are intended to be within the scope ofthe present invention.

The compounds of formula (I) may be in the form of pharmaceuticallyacceptable salts. Such salts are well known to those skilled in the art.S. M. Berge et al. describe pharmaceutically acceptable salts in detailin J. Pharmaceutical Sciences, 1977, 66:1-19. Pharmaceuticallyacceptable salts can be prepared in situ during the final isolation andpurification of compounds of the formula (I), or separately by reactingthe free base compound with a suitable organic acid. Suitablepharmaceutically acceptable acid addition salts of the compounds of thepresent invention may be prepared from an inorganic acid or from anorganic acid. Examples of such inorganic acids are hydrochloric,hydrobromic, hydroiodic, nitric, carbonic, sulfuric, and phosphoricacid. Appropriate organic acids may be selected from aliphatic,cycloaliphatic, aromatic, heterocyclic carboxylic and sulfonic classesof organic acids, examples of which are formic, acetic, propionic,succinic, glycolic, gluconic, lactic, malic, tartaric, citric, ascorbic,glucoronic, fumaric, maleic, pyruvic, alkyl sulfonic, arylsulfonic,aspartic, glutamic, benzoic, anthranilic, mesylic, salicylic,p-hydroxybenzoic, phenylacetic, mandelic, ambonic, pamoic, pantothenic,sulfanilic, cyclohexylaminosulfonic, stearic, algenic, β-hydroxybutyric,galactaric, and galacturonic acids. Suitable pharmaceutically acceptablebase addition salts of the compounds of the present invention includemetallic salts made from lithium, sodium, potassium, magnesium, calcium,aluminium, and zinc, and organic salts made from organic bases such ascholine, diethanolamine, morpholine. Alternatively, organic salts madefrom N,N′-dibenzylethylenediamine, chloroprocaine, choline,diethanolamine, ethylenediamine, meglumine (N-methylglucamine),procaine, ammonium salts, quaternary salts such as tetramethylammoniumsalt, amino acid addition salts such as salts with glycine and arginine.

The compounds of formula (I) also extend to include all derivatives withphysiologically cleavable leaving groups that can be cleaved in vivo toprovide the compounds of the formula (I). Suitable leaving groupsinclude acyl, phosphate, sulfate, sulfonate, and preferably are mono-,di- and per-acyl oxy-substituted compounds, where one or more of thependant hydroxy groups are protected by an acyl group, preferably anacetyl group. Typically, acyloxy substituted compounds are readilycleavable to the corresponding hydroxy-substituted compounds.

Representative compounds of the formula (I) may be synthesised asdescribed below.

In the first step of the synthesis, benzophenone intermediate (IV) isprepared from a suitably functionalized phenol (VI) and a suitablyfunctionalized benzoic acid (VII) according to Scheme 1.

The relative location of substituents R₁₄ and R₁₅ on the phenyl ring ofcompound (VII) may be selected based on the substitution patternrequired on the 4-phenyl ring of the compound of formula (I) beingprepared. Where appropriate or necessary, protecting groups may beemployed. Standard protecting groups are known to those skilled in theart and include those described, for example, in ‘Protective Groups inOrganic Synthesis’ by Theodora Greene and Peter Wuts (Third edition,1999, John Wiley and Sons).

Typically, in the reaction depicted in Scheme 1, the phenolic compound(VI) and the benzoic acid compound (VII) are reacted under acylatingconditions. For example, in one method described in the Indian Journalof Chemistry, 1971, 619-62, the phenolic compound (VI) and the benzoicacid compound (VII) may be combined with phosphorous oxychloride andzinc chloride and the mixture heated for a period of time sufficient forthe reaction to proceed substantially to completion. The precise periodof time will depend on the scale of the reaction, however those skilledin the art will readily be able to determine suitable time andtemperature conditions. In a typical reaction, the reagents are heatedat a temperature of about 70° C. for about 1 to 3 hours. When thereaction is judged to be sufficiently complete, the reaction mixture iscooled, for example by pouring onto ice, after which the benzophenoneintermediate (IV) may be isolated and purified using standard techniquesknown to those skilled in the art.

In an alternative method, the benzoic acid compound (VII) may be stirredin refluxing thionyl chloride for about 2 to 6 hours, followed byaddition of catalytic N,N-dimethylformamide in a suitable organicsolvent (for example dichloromethane), for about 20 mins to 1 hour.After removing residual thionyl chloride the mixture is typically cooled(for example in an ice bath) then aluminium chloride and the phenoliccompound (VI) are added and the mixture stirred for a suitable period oftime, typically about 18 to 36 hours, while slowly warming to roomtemperature, then heated at reflux for about 2 to 8 hours. The reactionmay be conducted under an inert atmosphere.

The benzophenone intermediate (IV) may be purified using standardtechniques known to those skilled in the art. For example, thebenzophenone intermediate (IV) may be collected by filtration, washed(for example with water), then recrystallised from a suitable solventsystem. Examples of recrystallisation solvents include methanol,ethanol, water and mixtures thereof. Alternatively, the benzophenoneintermediate (IV) may be purified by column chromatography.

The next step of the synthesis involves reaction of the benzophenoneintermediate (IV) with a suitably functionalized phenylcarboxylic acid(V) to provide functionalized benzopyranone (II) (see Scheme 2). Therelative location of substituents R₁₁ and R₁₂ on the phenyl ring ofcompound (V) may be selected based on the substitution pattern requiredon the 3-phenyl ring of the compound of formula (I) being prepared.Where appropriate or necessary, protecting groups may be employed.

Typically, in the condensation reaction depicted in Scheme 2, thebenzophenone intermediate (IV) is reacted with the suitablyfunctionalized phenylacetic acid (V) in the presence of a base andacetic anhydride. Typically, the base is a non-nucleophilic base, suchas N,N-diisopropylethyl amine (DIEA), N-methylmorpholine ortriethylamine. During this reaction any hydroxy substituents present onthe phenyl rings may be converted to the corresponding acetate. Thereaction is typically carried out with heating at a temperature and fora period of time until the reaction is judged to be substantiallycomplete (for example by TLC or GC analysis). Those skilled in the artwill know that suitable time periods will depend on the scale of thereaction and the particular reagents employed. Typically, the reagentsmay be warmed at a temperature of about 40-60° C. (for example about 50°C.) for about 20 to 30 minutes to ensure that all of the reagents are insolution, then heated at a higher temperature, such as about 130-150° C.(for example about 135° C.), for about 6 to 48 hours (for example about18 hours). The functionlized benzopyranone (II) may be isolated byconventional means, such as solvent extraction (for example, using anorganic solvent such as ethyl acetate, chloroform, or the like), andwashing with aqueous alkaline solution (for example sodium carbonate, orsodium hydrogen carbonate solution), followed by standard purificationusing techniques known to those skilled in the art, such as columnchromatography, recrystallisation from a suitable solvent (for exampleethanol or an ethanol/water mixture), or trituation with a suitablesolvent (for example methanol, ethanol or mixtures thereof).

The next step of the synthesis involves reduction of the lactone of thefunctionalized benzopyranone (II) to provide functionalized chromenecompound (III) (see Scheme 3).

Typically, the reduction reaction is carried out by treating thebenzopyranone (II) with a suitable reducing agent capable of reducingthe ketone moiety of the pyranone ring. Preferably, the reducing reagentselectively reduces the ketone moiety of the pyranone ring but does notreduce the 3,4 double bond. The reduction may also deprotect anyacylated hydroxy groups present on the phenyl rings. Suitable reducingagents will be known to those skilled in the art and include boranereagents, such as, for example borane dimethylsulfide complex,decborane, 9-BBN and borane tetrahydrofuran complex. In some embodimentsthe reducing agent is borane dimethylsulfide. The reduction may befacilitated by the use of a chiral auxiliary. For example, boranedimethylsulfide is amenable to asymmetric ketone reduction using achiral oxazaborolidine catalyst (Corey, E. J.; Helal, C. J. Angew. Chem.Int. Ed. 1998, 1986). The reaction may be carried out in an organicsolvent, such as tetrahydrofuran, toluene or chloroform. The reactionmay be performed under an inert atmosphere at a temperature below roomtemperature, typically at a temperature from about -10° C. to about 10°C., or at about −5° C. to about 0° C., or at about 0° C., for about 15minutes to about 4 hours, typically for about 30 minutes to about 2hours. When the reduction reaction is judged to be complete (orsubstantially complete) the product may be isolated by acidic work upusing standard methods known to the skilled person, then purified usingconventional techniques such as column chromatography.

With globally deprotected chromene compound (III) in hand, the finalstep of the synthesis involves catalytic cisoid reduction of the olefinof chromene compound (III) to give compounds of the formula (I) (seeScheme 4).

The reduction of the double bond may be performed by hydrogenation usingreagents and conditions that are well known to those skilled in the art.Suitable reagents include heterogenous metal catalysts, such aspalladium and platinum catalysts in the presence of a hydrogenatmosphere. Presently preferred catalysts include, but are not limitedto, Pd/C, Pd(OH)₂/C, Pt/C, Raney Nickel, Rh catalysts, including chiralRh catalysts, such as Rh DIPAMP and Wilkinsons catalysts. Examples ofsuitable solvents include methanol and ethanol. The reaction may beperformed at room temperature or the reaction mixture may be heated (forexample to about 50 to 60° C.). Alternatively, the hydrogenationreaction may be performed under pressure. Those skilled in the art willreadily be able to determine when the reaction is complete (orsubstantially complete) using standard techniques (for example TLC,GC-MS). The product may be purified using standard techniques (forexample chromatography).

After purification, compounds of formula (I) may be substantially pure.For example, the compounds of formula (I) may be isolated in a formwhich is at least about 80%, 85%, 90%, 95%, 98%, 99%, 99.5% or 99.9%pure.

Compounds of the formula (I) may be obtained as racemic mixtures.Enantiomers may be isolated using techniques known to those skilled inthe art, including chiral resolution, supercritical fluid chromatographyand enantioselective syntheses. Individual enantiomers may be isolatedin a substantially pure form or in an enantiomeric excess (ee). Forexample, in preferred embodiments an enantiomer may be isolated in anenantiomeric excess of about 70%, 75%, 80%, 85%, 90%, 92%, 95%, 96%,97%, 98%, 99% or greater than 99%.

The present inventors have discovered that compounds of the formula (I)are able to exert surprisingly powerful biological effects ondifferentiated cancer cells as well as on undifferentiated cancer cells,which are variously referred to as “cancer stem cells” or “cancerprogenitor cells”. The biological effects may include inhibition of cellproliferation, induction of cell death, induction of cellulardifferentiation and reversal of aberrant behavior.

The compounds of formula (I) therefore find use in the treatment ofcancer. In particular, the compounds of formula (I) may be used in thetreatment of cancer where it is desirable to target bothundifferentiated and differentiated cancer cells, and where the effecton both cancer cell types might be different or even opposite. Forexample, compounds of the formula (I) may induce cell death indifferentiated cancer cells and induce cellular differentiation inundifferentiated cancer cells. In other embodiments compounds of theformula (I) may inhibit the proliferation of cancer stem cells anddifferentiated cancer stem cells, such as somatic cancer cells.

The compounds of formula (I) may be used in conjunction with, oralternatively in the absence of, other chemotherapeutic agents.

The compounds of formula (I) may be used in the treatment of cancer thatis resistant to one or more chemotherapeutic agents.

By virtue of their biological effects on undifferentiated cancer cellsthe compounds of formula (I) find particular use in treating cancer thathas recurred in a subject and in reducing the incidence of, or the riskof, reccurence of cancer in a subject deemed to be at risk of cancerrecurrence, for example a subject who is in cancer remission. Thesubject may be in remission from a solid tumour as defined herein. Thecompounds of formula (I) may also find use in inducing apoptosis in, orinhibiting the proliferation of, cancer stem cells. The compounds offormula (I) may also find use in treating diseases caused by cancer stemcells, such as cancer. The cancer may be a metastatic cancer.

Furthermore, compounds of the formula (I) may possess superiorpharmaceutical properties, such as improved resistance to conjugationvia glucuronyl transferases and other water-solubilising transferasessuch as sulfases, which may be over-expressed on proliferative cells,such as cancer cells. This may advantageously confer superiorpharmaceutical properties, such as an enhanced pharmacokinetic profilethrough reduced conjugation and elimination.

In all aspects of the invention the cancer may be a solid tumour, suchas for example, breast cancer, lung cancer (NSCLC and SCLC), prostatecancer, ovarian cancer, uterine cancer, peritoneal cancer, brain cancer(including, for example, gliomas such as glioblastoma, Diffuse IntrinsicPontine Glioma (DIPG) and medulloblastoma), skin cancer, colon cancer,bladder cancer, colorectal cancer, gastric cancer, liver cancer,pancreatic cancer, head and neck cancer, melanoma, malignant ascites,mesothelioma or neuroblastoma. The brain cancer may be adult orpaediatric. The glioma may be temozolomide (TMZ) resistant or TMZsusceptible.

In particular embodiments the cancer is ovarian cancer, neuroblastoma,prostate cancer or brain cancer (including, for example, gliomas such asglioblastoma, DIPG and medulloblastoma). In other embodiments the canceris ovarian cancer, prostate cancer or brain cancer (including, forexample, gliomas such as glioblastoma, DIPG and medulloblastoma). Infurther embodiments the cancer is ovarian cancer, glioma, colorectalcancer, prostate cancer, breast cancer, lung cancer, liver cancer,melanoma or malignant ascites. In other embodiments the cancer may bepancreatic cancer, colorectal cancer, melanoma, prostate cancer, braincancer (including paediatric and adult), ovarian cancer, breast cancer,lung cancer, liver cancer, uterine cancer, neuroblastoma, mesothelioma,malignant ascites or peritoneal cancer.

Compounds of formula (I) may find use in inducing apoptosis in, orinhibiting the proliferation of ovarian cancer stem cells. Accordingly,in one embodiment the invention provides a method for inducing apoptosisin, or inhibiting the proliferation of ovarian cancer stem cells, themethod comprising contacting the ovarian cancer stem cells with aneffective amount of a compound of formula (I). The compound of formula(I) may be any combination of one or more of compounds 1 to 41. Thecompound of formula (I) may be selected from compounds 1 to 14 and32-41, or alternatively the compound of formula (I) may be selected fromcompounds 1 to 14 and 32-40, or alternatively may be selected fromcompounds 1 to 14, or alternatively may be selected from compounds 2, 6,9, 13 and 36, or alternatively may be selected from compounds 2, 6, 9and 13. The compound of formula (I) may be compound 2. The compounds offormula (I) may be used in the absence of other chemotherapeutic agents.The compounds may be in the form of the (+) enantiomer. The ovariancancer stem cells may be resistant to cisplatin and/or paclitaxel. Thecompound of formula (I) may be administered intraperitoneally.

Compounds of formula (I) may find use in treating ovarian cancer in asubject. Accordingly, in one embodiment the invention provides a methodfor the treatment of ovarian cancer in a subject in need thereof, themethod comprising administration to the subject of a therapeuticallyeffective amount of a compound of formula (I). The cancer may be acancer that has recurred. The compound of formula (I) may be anycombination of one or more of compounds 1 to 41. The compound of formula(I) may be selected from compounds 1 to 14 and 32-41, or alternativelythe compound of formula (I) may be selected from compounds 1 to 14 and32-40, or alternatively may be selected from compounds 1 to 14, oralternatively may be selected from compounds 2, 6, 9, 13 and 36, oralternatively may be selected from compounds 2, 6, 9 and 13. Thecompound of formula (I) may be compound 2. The compounds of formula (I)may be used in the absence of other chemotherapeutic agents. Thecompounds may be in the form of the (+) enantiomer. The ovarian cancermay be resistant to cisplatin and/or paclitaxel. The compound of formula(I) may be administered intraperitoneally.

Compounds of formula (I) may find use in reducing the incidence of, orthe risk of, cancer recurrence in a subject deemed to be at risk ofcancer recurrence. Accordingly, in one embodiment the invention providesa method for reducing incidences of, or risk of, cancer recurrence in asubject deemed to be at risk of cancer recurrence, the method comprisingadministration to the subject of an effective amount of a compound offormula (I). The subject deemed to be at risk of cancer recurrence maybe a subject in remission from ovarian cancer or a subject in remissionfrom brain cancer, such as glioma. The method may involve reducingincidences of, or risk of, ovarian cancer recurrence or brain cancerrecurrence in the subject. The compound of formula (I) may be anycombination of one or more of compounds 1 to 41. The compound of formula(I) may be selected from compounds 1 to 14, or alternatively may beselected from compounds 2, 6, 9 and 13. The compound of formula (I) maybe compound 2 or compound 9. The compounds of formula (I) may be used inthe absence of other chemotherapeutic agents. The compounds may be inthe form of the (+) enantiomer.

Compounds of formula (I) may find use in treating a disease in a subjectcaused by ovarian cancer stem cells. Accordingly, in one embodiment theinvention provides a method for treating a disease in a subject causedby ovarian cancer stem cells, the method comprising administration tothe subject of a therapeutically effective amount of a compound of theformula (I). The disease may be cancer. The cancer may be ovarian canceror some other cancer, for example a metastatic cancer. The cancer may beresistant to cisplatin and/or paclitaxel. The compound of formula (I)may be administered intraperitoneally. The compound of formula (I) maybe any combination of one or more of compounds 1 to 41. The compound offormula (I) may be selected from compounds 1 to 14, or alternatively maybe selected from compounds 2, 6, 9 and 13. The compound of formula (I)may be compound 2. The compounds of formula (I) may be used in theabsence of other chemotherapeutic agents. The compounds may be in theform of the (+) enantiomer.

Compounds of formula (I) may find use in inducing apoptosis in, orinhibiting the proliferation of brain cancer stem cells, such as gliomastem cells. Accordingly, in one embodiment the invention provides amethod for inhibiting the proliferation of brain cancer stem cells, suchas glioma stem cells, the method comprising contacting the brain cancerstem cells with an effective amount of a compound of formula (I). Thecompound of formula (I) may be any combination of one or more ofcompounds 1 to 41. The compound of formula (I) may be selected fromcompounds 1 to 14 and 32-41, or alternatively the compound of formula(I) may be selected from compounds 1 to 14 and 32-40, or alternativelymay be selected from compounds 1 to 14, or alternatively may be selectedfrom compounds 2, 6, 9 and 36, or alternatively may be selected fromcompounds 2, 6 and 9, or alternatively may be selected from compounds 2,6, 9 and 13, or alternatively may be selected from compounds 2 and 9.The compound of formula (I) may be compound 9. The compounds of formula(I) may be used in the absence of other chemotherapeutic agents. Thecompounds may be in the form of the (+) enantiomer.

Compounds of formula (I) may find use in treating a disease in a subjectcaused by brain cancer stem cells, such as glioma stem cells.Accordingly, in one embodiment the invention provides a method fortreating a disease in a subject caused by brain cancer stem cells, suchas glioma stem cells, the method comprising administration to thesubject of a therapeutically effective amount of a compound of theformula (I). The disease may be cancer. The cancer may be brain canceror some other cancer, for example a metastatic cancer. The compound offormula (I) may be any combination of one or more of compounds 1 to 41.The compound of formula (I) may be selected from compounds 1 to 14 and32-41, or alternatively the compound of formula (I) may be selected fromcompounds 1 to 14 and 32-40, or alternatively may be selected fromcompounds 1 to 14, or alternatively may be selected from compounds 2, 6,9 and 36, or alternatively may be selected from compounds 2, 6 and 9, oralternatively may be selected from compounds 2, 6, 9 and 13, oralternatively may be selected from compounds 2 and 9. The compound offormula (I) may be compound 9. The compounds of formula (I) may be usedin the absence of other chemotherapeutic agents. The compounds may be inthe form of the (+) enantiomer.

In another embodiment the invention provides a method for treatingcancer in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount of acompound of the formula (I). The cancer may be colorectal cancer, braincancer (such as for example, glioma, DIPG or medulloblastoma), ovariancancer, pancreatic cancer, prostate cancer, breast cancer, lung cancer,liver cancer, melanoma, neuroblastoma or malignant ascites. The braincancer may be adult or paediatric. The cancer may be ovarian cancer,prostate cancer, brain cancer or neuroblastoma. The cancer may beovarian cancer, prostate cancer or brain cancer. The compound of formula(I) may be any combination of one or more of compounds 1 to 41. Thecompound of formula (I) may be selected from compounds 1 to 14, 16,18-22, 24 or 32-41, or alternatively may be selected from compounds 1 to14, 16, 18-22, 24 or 32-40, or alternatively may be selected fromcompounds 1 to 14, 16, 18-22, 24 or 32-36, or alternatively may beselected from compounds 1 to 14, 16, 18-22, 24 or 32-35, oralternatively may be selected from compounds 2, 6, 9, 13 and 36, oralternatively may be selected from compounds 2, 6, 9 and 13. Thecompounds of formula (I) may be used in the absence of otherchemotherapeutic agents. The compounds may be in the form of the (+)enantiomer.

In another embodiment the invention provides a method for treating braincancer in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount of acompound of the formula (I). The brain cancer may be glioma, for exampleglioblastoma, DIPG or medulloblastoma. The brain cancer may be adult orpaediatric. The cancer may be a cancer that has recurred. The compoundof formula (I) may be any combination of one or more of compounds 1 to41. The compound of formula (I) may be selected from compounds 1 to 14and 32-41, or alternatively the compound of formula (I) may be selectedfrom compounds 1 to 14 and 32-40, or alternatively may be selected fromcompounds 1 to 14, or alternatively may be selected from compounds 2, 6,9 and 36, or alternatively may be selected from compounds 2, 6, 9 and13, or alternatively may be selected from compounds 2, 6 and 9, oralternatively may be selected from compounds 2, 6, 9 and 13, oralternatively may be selected from compounds 2 and 9. The compound offormula (I) may be compound 9. The compounds of formula (I) may be usedin the absence of other chemotherapeutic agents. The glioma may beTMZ-resistant or susceptible to TMZ. The compounds may be in the form ofthe (+) enantiomer.

In still a further embodiment the invention provides a method fortreating prostate cancer in a subject in need thereof, the methodcomprising administration to the subject of a therapeutically effectiveamount of a compound of the formula (I). The compound of formula (I) maybe any combination of one or more of compounds 1 to 41. The compound offormula (I) may be selected from compounds 2, 6, 9, 19-22, 24 and 32 to41, or alternatively may be selected from compounds 2, 6, 9, 19-22, 24and 32 to 40. The compound of formula (I) may be selected from compounds33 to 41 or from compounds 33 to 40. The compound of formula (I) may becompound 33 or 36. The compound of formula (I) may be compound 36. Thecompounds of formula (I) may be used in the absence of otherchemotherapeutic agents. The compounds may be in the form of the (+)enantiomer. The compound of formula (I) may be administered rectally.

In still a further embodiment the invention provides a method fortreating neuroblastoma in a subject in need thereof, the methodcomprising administration to the subject of a therapeutically effectiveamount of a compound of the formula (I). The compound of formula (I) maybe any combination of one or more of compounds 1 to 41. The compound offormula (I) may be selected from compounds 2, 6, 9, 19-22, 24 and 32 to41, or alternatively may be selected from compounds 2, 6, 9, 19-22, 24and 32 to 40. The compound of formula (I) may be compound 9 or compound36. The neuroblastoma may be paediatric neuroblastoma. The compounds offormula (I) may be used in the absence of other chemotherapeutic agents.The compounds may be in the form of the (+) enantiomer.

In still a further embodiment the invention provides a method fortreating melanoma in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount of acompound of the formula (I). The compound of formula (I) may be anycombination of one or more of compounds 1 to 41. The compound of formula(I) may be selected from compounds 2, 6, 9, 19-22, 24 and 32 to 41, oralternatively may be selected from compounds 2, 6, 9, 19-22, 24 and 32to 40. The compound of formula (I) may be compound 9. The compounds offormula (I) may be used in the absence of other chemotherapeutic agents.The compounds may be in the form of the (+) enantiomer.

In yet another embodiment the invention provides a method for treatingmalignant ascites in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount of acompound of the formula (I). The compound of formula (I) may be anycombination of one or more of compounds 1 to 41. The compound of formula(I) may be selected from compounds 2, 6, 9, 19-22, 24 and 32 to 41, oralternatively may be selected from compounds 2, 6, 9, 19-22, 24 and 32to 40. The compound of formula (I) may be compound 2 or compound 9. Thecompound of formula (I) may be compound 2. The compounds of formula (I)may be used in the absence of other chemotherapeutic agents. Thecompounds may be in the form of the (+) enantiomer.

In another embodiment the invention provides a method for treatingovarian cancer peritoneal cancer, malignant ascites, uterine cancer,pancreatic cancer, gastric cancer, colorectal cancer, liver cancer,breast cancer, lung cancer or prostate cancer, in a subject in needthereof, the method comprising administration to the subject of atherapeutically effective amount of compound 2. The compound may be usedin the absence of other chemotherapeutic agents. The compound may be inthe form of the (+) enantiomer.

In another embodiment the invention provides a method for treating braincancer, neuroblastoma, melanoma, ovarian cancer, pancreatic cancer, lungcancer, liver cancer, colorectal cancer or prostate cancer, in a subjectin need thereof, the method comprising administration to the subject ofa therapeutically effective amount of compound 9. The brain cancer maybe glioma, for example, DIPG. The compound may be used in the absence ofother chemotherapeutic agents. The compound may be in the form of the(+) enantiomer.

In another embodiment the invention provides a method for treatingprostate cancer, brain cancer, lung cancer, liver cancer, breast cancer,melanoma, pancreatic cancer, ovarian cancer or colorectal cancer, in asubject in need thereof, the method comprising administration to thesubject of a therapeutically effective amount of compound 36. The braincancer may be glioma, for example, DIPG. The compound may be used in theabsence of other chemotherapeutic agents. The compound may be in theform of the (+) enantiomer.

In another embodiment the invention provides a method for treating livercancer in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount ofcompound 20 or compound 33. The compounds may be used in the absence ofother chemotherapeutic agents. The compounds may be in the form of the(+) enantiomer.

Those skilled in the art will recognise that compounds andpharmaceutical compositions of the present invention may be administeredvia any route which delivers an effective amount of the compounds to thetissue or site to be treated. In general, the compounds and compositionsmay be administered by the parenteral (for example intravenous,intraspinal, subcutaneous or intramuscular), oral or topical route.Administration may be systemic, regional or local. In one embodimentadministration may be rectal.

The particular route of administration to be used in any givencircumstance will depend on a number of factors, including the nature ofthe cancer to be treated, the severity and extent of the cancer, therequired dosage of the particular compound to be delivered and thepotential side-effects of the compound.

In general, suitable compositions may be prepared according to methodsthat are known to those of ordinary skill in the art and may includepharmaceutically acceptable carriers, diluents and/or excipients. Thecarriers, diluents and excipients must be “acceptable” in terms of beingcompatible with the other ingredients of the composition, and notdeleterious to the recipient thereof.

Examples of pharmaceutically acceptable carriers or diluents aredemineralised or distilled water; saline solution; vegetable based oilssuch as peanut oil, safflower oil, olive oil, cottonseed oil, maize oilor coconut oil; silicone oils, including polysiloxanes, such as methylpolysiloxane, phenyl polysiloxane and methylphenyl polysiloxane;volatile silicones; mineral oils such as liquid paraffin, soft paraffinor squalane; cellulose derivatives such as methyl cellulose, ethylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose orhydroxypropylmethylcellulose; Cremaphor; cyclodextrins; lower alkanols,for example ethanol or i-propanol; lower aralkanols; lower polyalkyleneglycols or lower alkylene glycols, for example polyethylene glycol,polypropylene glycol, ethylene glycol, propylene glycol, 1,3-butyleneglycol or glycerin; fatty acid esters such as isopropyl palmitate,isopropyl myristate or ethyl oleate; polyvinylpyrridone; agar;carrageenan; gum tragacanth or gum acacia and petroleum jelly.Typically, the carrier or carriers will form from 10% to 99.9% by weightof the compositions.

Pharmaceutical compositions of the invention may be in a form suitablefor administration by injection, in the form of a formulation suitablefor oral ingestion (such as capsules, tablets, caplets, elixirs, forexample), in the form of an ointment, cream or lotion suitable fortopical administration, in a form suitable for delivery as an eye drop,in an aerosol form suitable for administration by inhalation, such as byintranasal inhalation or oral inhalation, in a form suitable forparenteral administration, that is, subcutaneous, intramuscular orintravenous injection.

For administration as an injectable solution or suspension, non-toxicparenterally acceptable diluents or carriers can include cyclodextrins(for example Captisol®) Cremaphor, Ringer's solution, isotonic saline,phosphate buffered saline, ethanol and 1,2 propylene glycol. To aidinjection and delivery, the compounds may also be added to PEG andnon-PEGylated liposomes or micelles with specific targeting tagsattached to PEG moieties, such as the RGD peptide or glutathione, foraiding passage across the blood brain barrier.

Some examples of suitable carriers, diluents, excipients and adjuvantsfor oral use include cyclodextrins, Cremaphor, peanut oil, liquidparaffin, sodium carboxymethylcellulose, methylcellulose, sodiumalginate, gum acacia, gum tragacanth, dextrose, sucrose, sorbitol,mannitol, gelatine and lecithin. In addition these oral formulations maycontain suitable flavouring and colourings agents. When used in capsuleform the capsules may be coated with compounds such as glycerylmonostearate or glyceryl distearate that delay disintegration.

Adjuvants typically include emollients, emulsifiers, thickening agents,preservatives, bactericides and buffering agents.

Solid forms for oral administration may contain binders acceptable inhuman and veterinary pharmaceutical practice, sweeteners, disintegratingagents, diluents, flavourings, coating agents, preservatives, lubricantsand/or time delay agents. Suitable binders include gum acacia, gelatine,corn starch, gum tragacanth, sodium alginate, carboxymethylcellulose orpolyethylene glycol. Suitable sweeteners include sucrose, lactose,glucose, aspartame or saccharin. Suitable disintegrating agents includecorn starch, methylcellulose, polyvinylpyrrolidone, guar gum, xanthangum, bentonite, alginic acid or agar. Suitable diluents include lactose,sorbitol, mannitol, dextrose, kaolin, cellulose, calcium carbonate,calcium silicate or dicalcium phosphate. Suitable flavouring agentsinclude peppermint oil, oil of wintergreen, cherry, orange or raspberryflavouring. Suitable coating agents include polymers or copolymers ofacrylic acid and/or methacrylic acid and/or their esters, waxes, fattyalcohols, zein, shellac or gluten. Suitable preservatives include sodiumbenzoate, vitamin E, alpha-tocopherol, ascorbic acid, methyl paraben,propyl paraben or sodium bisulphite. Suitable lubricants includemagnesium stearate, stearic acid, sodium oleate, sodium chloride ortalc. Suitable time delay agents include glyceryl monostearate orglyceryl distearate.

Liquid forms for oral administration may contain, in addition to theabove agents, a liquid carrier. Suitable liquid carriers include water,oils such as olive oil, peanut oil, sesame oil, sunflower oil, saffloweroil, coconut oil, liquid paraffin, ethylene glycol, propylene glycol,polyethylene glycol, ethanol, propanol, isopropanol, glycerol, fattyalcohols, triglycerides or mixtures thereof.

Suspensions for oral administration may further comprise dispersingagents and/or suspending agents. Suitable suspending agents includesodium carboxymethylcellulose, methylcellulose,hydroxypropylmethylcellulose, polyvinylpyrrolidone, sodium alginate oracetyl alcohol. Suitable dispersing agents include lecithin,polyoxyethylene esters of fatty acids such as stearic acid,polyoxyethylene sorbitol mono- or di-oleate, -stearate or -laurate,polyoxyethylene sorbitan mono- or di-oleate, -stearate or -laurate andthe like.

Emulsions for oral administration may further comprise one or moreemulsifying agents. Suitable emulsifying agents include dispersingagents as exemplified above or natural gums such as guar gum, gum acaciaor gum tragacanth.

Methods for preparing parenterally administrable compositions areapparent to those skilled in the art, and are described in more detailin, for example, Remington's Pharmaceutical Science, 15th ed., MackPublishing Company, Easton, Pa., hereby incorporated by referenceherein.

Topical formulations may comprise an active ingredient together with oneor more acceptable carriers, and optionally any other therapeuticingredients. Formulations suitable for topical administration includeliquid or semi-liquid preparations suitable for penetration through theskin to the site where treatment is required, such as liniments,lotions, creams, ointments or pastes, and drops suitable foradministration to the eye, ear or nose.

Drops according to the present invention may comprise sterile aqueous oroily solutions or suspensions. These may be prepared by dissolving theactive ingredient in an aqueous solution of a bactericidal and/orfungicidal agent and/or any other suitable preservative, and optionallyincluding a surface active agent. The resulting solution may then beclarified by filtration, transferred to a suitable container andsterilised. Sterilisation may be achieved by autoclaving or maintainingat 90° C. to 100° C. for half an hour, or by filtration, followed bytransfer to a container by an aseptic technique. Examples ofbactericidal and fungicidal agents suitable for inclusion in the dropsare phenylmercuric nitrate or acetate (0.002%), benzalkonium chloride(0.01%) and chlorhexidine acetate (0.01%). Suitable solvents for thepreparation of an oily solution include glycerol, diluted alcohol andpropylene glycol.

Lotions according to the present invention include those suitable forapplication to the skin or eye. An eye lotion may comprise a sterileaqueous solution optionally containing a bactericide and may be preparedby methods similar to those described above in relation to thepreparation of drops. Lotions or liniments for application to the skinmay also include an agent to hasten drying and to cool the skin, such asan alcohol or acetone, and/or a moisiteriser such as glycerol, or oilsuch as olive oil.

Creams, ointments or pastes according to the present invention aresemi-solid formulations of the active ingredient for externalapplication. They may be made by mixing the active ingredient in finelydivided or powdered form, alone or in solution or suspension in anaqueous or non-aqueous fluid, with a greasy or non-greasy basis. Thebasis may comprise hydrocarbons such as hard, soft or liquid paraffin,glycerol, beeswax, a metallic soap; a mucilage; an oil of natural originsuch as almond, corn, arachis, castor or olive oil; wool fat or itsderivatives, or a fatty acid such as stearic or oleic acid together withan alcohol, such as propylene glycol or macrogols.

The composition may incorporate any suitable surfactant such as ananionic, cationic or non-ionic surfactant, such as sorbitan esters orpolyoxyethylene derivatives thereof. Suspending agents such as naturalgums, cellulose derivatives or inoraganic materials such as silicaceoussilicas, and other ingredients such a lanolin, may also be included.

In some embodiments the compositions are administered in the form ofsuppositories suitable for rectal administration of the compounds offormula (I). These compositions are prepared by mixing the compound offormula (I) with a suitable non-irritating excipient which is solid atordinary temperatures but liquid at the rectal temperature and willtherefore melt in the rectum to release the compound of formula (I).Such materials include cocoa butter, glycerinated gelatin, hydrogenatedvegetable oils, mixtures of polyethylene glycols of various molecularweights and fatty acid esters of polyethylene glycol.

The compositions may also be administered or delivered to target cellsin the form of liposomes. Liposomes are generally derived fromphospholipids or other lipid substances and are formed by mono- ormulti-lamellar hydrated liquid crystals that are dispersed in an aqueousmedium. Specific examples of liposomes used in administering ordelivering a composition to target cells are synthetic cholesterol(Sigma), the phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine(DSPC); Avanti Polar Lipids), the PEG lipid 3-N-[(-methoxy poly(ethyleneglycol)2000)carbamoyl]-1,2-dimyrestyloxy-propylamine (PEG-cDMA), and thecationic lipid 1,2-di-o-octadecenyl-3-(N,N-dimethyl)aminopropane (DODMA)or 1,2-dilinoleyloxy-3-(N,N-dimethyl)aminopropane (DLinDMA) in the molarratios 55:20:10:15 or 48:20:2:30, respectively, PEG-cDMA, DODMA andDLinDMA. The liposome may be contructed from1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (D SPE PEG2000) and phosphatidylycholine derived from soyand hydrogenated between 50-100%, for example Soy PC-75 or Soy PC-100.Differing MW PEG's may be used and covalently bound with variousspecific targeting agents such as glutathione, RGD peptides or otherrecognized liposome targeting agents. Any non-toxic, physiologicallyacceptable and metabolisable lipid capable of forming liposomes can beused. The compositions in liposome form may contain stablisers,preservatives, excipients and the like. The preferred lipids are thephospholipids and the phosphatidyl cholines (lecithins), both naturaland synthetic. Methods to form liposomes are known in the art, and inrelation to this, specific reference is made to: Prescott, Ed., Methodsin Cell Biology, Volume XIV, Academic Press, New York, N.Y. (1976), p.33 et seq., the contents of which is incorporated herein by reference.

The compositions may also be administered in the form of microparticlesor nanoparticles. Biodegradable microparticles formed from polyactide(PLA), polylactide-co-glycolide (PLGA), and epsilon-caprolactone(-caprlactone) have been extensively used as drug carriers to increaseplasma half life and thereby prolong efficacy (R. Kumar, M., 2000, J.Pharm. Pharmaceut. Sci. 3(2) 234-258). Microparticles have beenformulated for the delivery of a range of drug candidates includingvaccines, antibiotics, and DNA. Moreover, these formulations have beendeveloped for various delivery routes including parenteral subcutaneousinjection, intravenous injection and inhalation.

The compositions may incorporate a controlled release matrix that iscomposed of sucrose acetate isobutyrate (SAIB) and an organic solvent ororganic solvents mixture. Polymer additives may be added to the vehicleas a release modifier to further increase the viscosity and slow downthe release rate. SAIB is a well known food additive. It is a veryhydrophobic, fully esterified sucrose derivative, at a nominal ratio ofsix isobutyrate to two acetate groups. As a mixed ester, SAIB does notcrystallise but exists as a clear viscous liquid. Mixing SAIB with apharmaceutically acceptable organic solvent, such as ethanol or benzylalcohol decreases the viscosity of the mixture sufficiently to allow forinjection. An active pharmaceutical ingredient may be added to the SAIBdelivery vehicle to form SAIB solution or suspension formulations. Whenthe formulation is injected subcutaneously, the solvent differs from thematrix allowing the SAIB-drug or SAIB-drug-polymer mixtures to set up asan in situ forming depot.

For the purposes of the present invention compounds and compositions maybe administered to subjects either therapeutically or preventively. In atherapeutic application compositions are administered to a patientalready suffering from cancer in an amount sufficient to cure or atleast partially arrest the cancer and its complications. The compositionshould provide a quantity of the compound or agent sufficient toeffectively treat the subject.

The therapeutically effective amount for any particular subject willdepend upon a variety of factors including: the cancer being treated andthe severity thereof; the activity of the compound administered; thecomposition in which the compound is present; the age, body weight,general health, sex and diet of the subject; the time of administration;the route of administration; the rate of sequestration of the compound;the duration of the treatment; drugs used in combination or coincidentalwith the compound, together with other related factors well known inmedicine.

One skilled in the art would be able, by routine experimentation, todetermine an effective, non-toxic amount of a compound that would berequired to treat or prevent a particular cancer.

Generally, an effective dosage is expected to be in the range of about0.0001 mg to about 1000 mg per kg body weight per 24 hours; typically,about 0.001 mg to about 750 mg per kg body weight per 24 hours; about0.01 mg to about 500 mg per kg body weight per 24 hours; about 0.1 mg toabout 500 mg per kg body weight per 24 hours; about 0.1 mg to about 250mg per kg body weight per 24 hours; about 1.0 mg to about 250 mg per kgbody weight per 24 hours. More typically, an effective dose range isexpected to be in the range about 1.0 mg to about 200 mg per kg bodyweight per 24 hours; about 1.0 mg to about 100 mg per kg body weight per24 hours; about 1.0 mg to about 50 mg per kg body weight per 24 hours;about 1.0 mg to about 25 mg per kg body weight per 24 hours; about 5.0mg to about 50 mg per kg body weight per 24 hours; about 5.0 mg to about20 mg per kg body weight per 24 hours; about 5.0 mg to about 15 mg perkg body weight per 24 hours.

Alternatively, an effective dosage may be up to about 500 mg/m².Generally, an effective dosage is expected to be in the range of about25 to about 500 mg/m², preferably about 25 to about 350 mg/m², morepreferably about 25 to about 300 mg/m², still more preferably about 25to about 250 mg/m², even more preferably about 50 to about 250 mg/m²,and still even more preferably about 75 to about 150 mg/m².

Typically, in therapeutic applications, the treatment would be for theduration of the disease state.

Further, it will be apparent to one of ordinary skill in the art thatthe optimal quantity and spacing of individual dosages will bedetermined by the nature and extent of the cancer being treated, theform, route and site of administration, and the nature of the particularindividual being treated. Also, such optimum conditions can bedetermined by conventional techniques.

The compounds of formula (I) may be used alone in the treatment ofcancer, or alternatively in combination with radiotherapy and/or surgeryand/or other therapeutic agents, for example chemotherapeutic agents andimmunostimulatory agents, as part of a combination therapy. Thecompounds of formula (I) may sensitise undifferentiated cancer cells toother chemotherapeutic agents and/or radiotherapy.

The terms “combination therapy” and “adjunct therapy” are intended toembrace administration of multiple therapeutic agents in a sequentialmanner in a regimen that will provide beneficial effects and is intendedto embrace administration of these agents in either a single formulationor in separate formulations.

Combination therapy may involve the active agents being administeredtogether, sequentially, or spaced apart as appropriate in each case.Combinations of active agents including compounds of the invention maybe synergistic.

The co-administration of compounds of the formula (I) with othertherapeutic agent(s) may be effected by a compound of the formula (I)being in the same unit dose form as the other therapeutic agent(s), orthe compound of the formula (I) and the other therapeutic agent(s) maybe present in individual and discrete unit dosage forms that areadministered sequentially, at the same, or at a similar time. Sequentialadministration may be in any order as required, and may require anongoing physiological effect of the first or initial agent to be currentwhen the second or later agent is administered, especially where acumulative or synergistic effect is desired. When administeredseparately, it may be preferred for the compound of formula (I) and theother agent to be administered by the same route of administration,although it is not necessary for this to be so.

In accordance with various embodiments of the present invention one ormore compounds of formula (I) may be included in combination therapywith surgery and/or radiotherapy and/or one or more chemotherapeuticagents.

There are large numbers of chemotherapeutic agents that are currently inuse, in clinical evaluation and in pre-clinical development, which couldbe selected for treatment of cancers in combination with compounds ofthe formula (I). Such agents fall into several major categories, namely,antibiotic-type agents, alkylating agents, anti-metabolite agents,hormonal agents, immunological agents, interferon-type agents and acategory of miscellaneous agents. Alternatively, other chemotherapeuticagents, such as metallomatrix proteases (MMP) inhibitors may be used.Suitable agents which may be used in combination therapies include thoselisted, for example, in the Merck Index, An Encyclopaedia of Chemicals,Drugs and Biologicals, 12th Ed., 1996, the entire contents of which areincorporated herein by reference.

When used in the treatment of solid tumours compounds of the formula (I)may be administered with one or more of the following chemotherapeuticagents: adriamycin, taxol, docetaxel, fluorouracil, melphalan,cisplatin, alpha interferon, COMP (cyclophosphamide, vincristine,methotrexate and prednisone), etoposide, mBACOD (methotrexate,bleomycin, doxorubicin, cyclophosphamide, vincristine anddexamethasone), PROMACE/MOPP (prednisone, methotrexate (w/leucovinrescue), doxorubicin, cyclophosphamide, taxol,etoposide/mechlorethamine, vincristine, prednisone and procarbazine),vincristine, vinblastine, angioinhibins, TNP 470, pentosan polysulfate,platelet factor 4, angiostatin, LM 609, SU 101, CM 101, Techgalan,thalidomide, SP-PG and the like.

The present invention is further described below by reference to thefollowing non-limiting examples.

EXAMPLES Example 1 Synthesis of Compounds of Formula (I)

Representative compounds of the formula (I) were prepared as follows.

1a R₁ = Me, R₂, R₃ = H, R₁₃, R₁₅ = H, R₁₄ = OH 1j R₁ = Me, R₂, R₃ = H,R₁₃, R₁₅ = H, R₁₄ = NHAc 1b R₁, R₂, R₃, R₁₅ = H, R₁₃ = F, R₁₄ = OH 1k R₁= Me, R₂ = Et, R₃, R₁₃, R₁₅ = H, R₁₄ = OH 1c R₁ = Me, R₂, R₃, R₁₅ = H,R₁₃ = F, R₁₄ = OH 1l R₁ = Et, R₂, R₃, R₁₃, R₁₅ = H R₁₄ = OH 1d R₁, R₂,R₃, R₁₃, R₁₅ = Me, R₁₄ = OMe 1m R₂ = Me, R₁, R₃, R₁₃, R₁₅ = H, R₁₄ = OH1e R₁ = Me, R₂, R₃ = H, R₁₃, R₁₅ = F, R₁₄ = OH 1n R₃, R₁₃ = F, R₁, R₂,R₁₅ = H, R₁₄ = OH 1f R₁ = iPr, R₂, R₃, R₁₅ = H, R₁₃ = F, R₁₄ = OH 1o R₂= Cl, R₁, R₃, R₁₅ = H, R₁₃ = F, R₁₄ = OH 1g R₁, R₃, R₁₅ = H, R₂ = Et,R₁₃ = F, R₁₄ = OH 1p R₁ = Me, R₂, R₃, R₁₅ = H, R₁₃ = Cl, R₁₄ = OH 1h R₁= Me, R₂, R₃, R₁₅ = H, R₁₃, R₁₄ = —OCH₂O— 1q R₁ = Me, R₂ = Et, R₃, R₁₅ =H, R₁₃ = F, R₁₄ = OH 1i R₁ = Me, R₂, R₃ = H, R₁₃, R₁₅ = H, R₁₄ = NH₂ 1rR₁ = Me, R₂ = Et, R₃, R₁₅ = H, R₁₃ = Me, R₁₄ = OH 1s R₁ = Me, R₂ = Et,R₃, R₁₅ = H R₁₃ = Me, R₁₄ = OH 1t R₁ = Me, R₂ = Et, R₃, R₁₅ = H R₁₃ = F,R₁₄ = OH

a R₁ = Me, R₁₀, R₁₁, R₁₂ = OMe, R₂, R₃, R₁₃, R₁₅ = H, R₁₄ = OH o R₁ =iPr, R₂, R₃, R₁₅ = H, R₁₃ = F, R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH b R₁ = Me,R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH, R₂, R₃, R₁₃, R₁₅ = H p R₁, R₃, R₁₅ = H,R₂ = Et, R₁₃ = F, R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH c R₁ = Me, R₁₀, R₁₂ =t-Bu, R₁₁, R₁₄ = OH, R₂, R₃, R₁₃, R₁₅ = H q R₁ = Me, R₂, R₃, R₁₅ = H,R₁₀, R₁₂ = OMe, R₁₁ = OH, R₁₃, R₁₄ = —OCH₂O— d R₁ = Me, R₁₀, R₁₁, R₁₂ =F, R₂, R₃, R₁₃, R₁₅ = H, R₁₄ = OH r R₁ = Me, R₂, R₃ = H, R₁₃, R₁₅ = H,R₁₀, R₁₂ = OMe, R₁₁ = OH, R₁₄ = NH₂ e R₁, R₂, R₃, R₁₅ = H, R₁₀, R₁₁,R₁₂, R₁₃ = F, R₁₄ = OH s R₁ = Me, R₂, R₃ = H, R₁₃, R₁₅ = H, R₁₀, R₁₂ =OMe, R₁₁ = OH, R₁₄ = NHEt f R₁, R₂, R₃, R₁₅ = H, R₁₀, R₁₂ = OMe, R₁₁,R₁₄ = OH, R₁₃ = F t R₁ = Me, R₂ = Et, R₃, R₁₃, R₁₅ = H, R₁₀, R₁₂ = OMe,R₁₁, R₁₄ = OH g R₁, R₂, R₃, R₁₅ = H, R₁₀, R₁₁, R₁₂ = OMe, R₁₃ = F, R₁₄ =OH u R₁ = Et, R₂, R₃, R₁₃, R₁₅ = H, R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH h R₁ =Me, R₁₀, R₁₁, R₁₂, R₁₃ = F, R₁₄ = OH, R₂, R₃, R₁₅ = H v R₂ = Me, R₁, R₃,R₁₃, R₁₅ = H, R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH i R₁ = Me, R₁₀, R₁₂ = OMe,R, R₁₄ = OH, R₁₃ = F, R₂, R₃, R₁₅ = H w R₃, R₁₃ = F, R₁, R₂, R₁₅ = H,R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH j R₁ = Me, R₁₀, R₁₁, R₁₂ = OMe, R₁₃ = F,R₁₄ = OH, R₂, R₃, R₁₅ = H x R₂ = Cl, R₂, R₃, R₁₅ = H, R₁₃ = Cl, R₁₀, R₁₂= OMe, R₁₁, R₁₄ = OH k R₁, R₁₃, R₁₅ = Me, R₁₀, R₁₂, R₁₄ = OMe, R₂, R₃,R₁₁ = OH y R₁ = Me, R₂, R₃, R₁₅ = H, R₁₃ = Cl, R₁₀, R₁₂ = OMe, R₁₁, R₁₄= OH l R₁, R₁₃, R₁₅ = Me, R₁₀, R₁₁, R₁₂, R₁₄ = OMe, R₂, R₃ = H z R₁ =Me, R₂ = Et, R₃, R₁₅ = H, R₁₀, R₁₃ = OMe, R₁₃ = F, R₁₁, R₁₄ = OH m R₁ =Me, R₁₀, R₁₂ = OMe, R₁₁, R₁₄ = OH, R₁₃, R₁₅ = F, R₂, R₃ = H aa R₁ = Me,R₂ = Et, R₃, R₁₅ = H, R₁₀, R₁₃ = OMe, R₁₃ = Me, R₁₁, R₁₄ = OH n R₁ = Me,R₁₀, R₁₁, R₁₂ = OMe, R₁₃, R₁₅ = F, R₁₄ = OH, R₂, R₃ = H bb R₁ = Me, R₂ =Et, R₃, R₁₅ = H, R₁₀, R₁₃ = Me, R₁₃ =F, R₁₁, R₁₄ = OH cc R₁ = Me, R₂ =Et, R₃, R₁₅ = H, R₁₀, R₁₃ = OMe, R₁₃ = Me, R₁₁, R₁₄ = OH dd R₁ = Me, R₂= Et, R₃, R₁₅ = H, R₁₀, R₁₃ = Me, R₁₃ = F, R₁₁, R₁₄ = OH

Step 1. ZnCl₂, POCl₃, 70° C., 2 h; Step 2. DiPEA, Ac₂O, 135° C., 18 h.Step 3. THF, BH₃.Me₂S in THF, 35° C., 18 h; Step 4. H₂ Pd/C, EtOH, 3bar, 40° C., 18 h.

Step 1. (2,4-Dihydroxy-3-methylphenyl)(4-hydroxyphenyl) methanone (1-1a)

2-Methylresorcinol (50 g, 1 eq.), 4-hydroxybenzoic acid (55.5 g, 1 eq.),zinc chloride (120 g, 2.2 eq) and POCl₃ (550 mL) was added to a flaskunder N₂ and set stirring. The mixture was heated to 70° C. for 2 hrs,cooled to r.t. and poured onto ice/water (4 L) keeping the temperatureat <30° C. The solid was filtered, washing with water (3×500 mL). Thedamp solid was then recrystallised from IMS (250 mL) and dried to affordthe product as an orange solid 85 g (87%). ¹H NMR (300 MHz, DMSO-d₆) δ12.91 (s, 1H), 10.59 (s, 1H), 10.30 (s, 1H), 7.28 (d, J=8.9 Hz, 2H),7.18 (d, J=7.8 Hz, 1H), 6.46 (d, J=8.9 Hz, 2H), 6.24 (d, J=7.8 Hz, 1H),2.02 (s, 3H).

Other analogues prepared by this method:

(2,4-Dihydroxyphenyl)(3-fluoro-4-hydroxyphenyl)methanone (1-1b) (47%).¹H NMR (300 MHz, DMSO-d₆) δ 11.90 (bs, 1H), 7.51-7.32 (m, 3H), 7.09 (t,J=8.5 Hz, 1H), 6.45-6.33 (m, 2H).

(2,4-Dihydroxy-3-methylphenyl)(3-fluoro-4-hydroxyphenyl)methanone (1-1c)(41%). ¹H NMR (400 MHz, DMSO-d₆) δ 12.72 (s, 1H), 10.76 (s, 1H), 10.65(s, 1H), 7.43 (dd, J=1.96, 11.74 Hz, 1H), 7.33 (d, J=9.00 Hz, 2H), 7.06(t, J=8.41 Hz, 1H), 6.45 (d, J=9.00 Hz, 1H), 1.99 (s, 3H).

(2,4-Dihydroxy-3-methylphenyl)(4-methoxy-3,5-dimethylphenyl)methanone(1-1d) (63%). ¹H NMR (300 MHz, DMSO-d₆) δ12.89 (s, 1H), 10.67 (s, 1H),10.15 (s, 1H), 7.38-7.15 (m, 3H), 6.52-6.43 (m, 1H), 3.72 (s, 3H), 2.28(s, 6H).

(3,5-Difluoro-4-hydroxyphenyl)(2,4-dihydroxy-3-methylphenyl)methanone(1-1e) (43%). ¹H NMR (300 MHz, DMSO-d₆) δ 12.61 (s, 1H), 10.84 (bs, 1H),9.70 (bs, 1H), 7.23-7.10 (m, 2H), 6.98-6.85 (m, 1H), 2.20 (s, 3H).

(2,4-Dihydroxy-3-i-propylphenyl)(3-fluoro-4-hydroxyphenyl)methanone(1-1f) (18%). ¹H NMR (300 MHz, DMSO-d₆) δ 12.88 (bs, 1H), 7.62 (d, J=8.9Hz, 2H), 7.31 (d, J=8.4 Hz, 1H), 7.12 (d, J=8.9 Hz, 2H), 6.47 (d, J=8.4Hz, 1H), 1.95 (m, 2H), 1.65 (m, 2H), 1.2 (t, J=9.1Hz, 3H).

(2,4-Dihydroxy-5-ethylphenyl)(3-fluoro-4-hydroxyphenyl)methanone (1-1g)(77%) ¹H NMR (300 MHz, DMSO-d₆) δ 7.41 (d, J=1.2 Hz, 1H), 7.32 (d, J=1.4Hz, 1H), 7.22 (dd, J=1.2, 8.2 Hz), 7.08 (d, J=1.2 Hz, 1H), 7.00 (d,J=8.1 Hz, 1H), 2.51 (q, J=9.1 Hz, 2H), 1.22 (t, J=9.2 Hz, 3H).

(2,4-Dihydroxy-3-methylphenyl)(3-4-methylenedioxyphenyl)methanone (1-1h)(22%) ¹H NMR (300 MHz, DMSO-d₆) δ 12.65 (br s, 1H), 9.87 (br s, 1H),7.38 (d, J=8.2Hz, 1H), 7.25 (m, 2H), 7.05 (d, J=8.3Hz, 1H), 6.43 (d,J=8.2Hz, 1H), 6.06 (s, 2H), 2.02 (s, 3H).

(2,4-Dihydroxy-3-methylphenyl)(4-nitrophenyl)methanone (1-1i) (38%) ¹HNMR (300 MHz, DMSO-d₆) δ 12.96 (br s, 1H), 8.33 (d, J=8.7 Hz, 2H), 7.97(d, J=8.8 Hz, 2H), 7.09 (d, J=8.12 Hz, 1H), 6.90 (d, J=8.2 Hz, 1H), 2.05(s, 3H).

(2,4-Dihydroxy-3-methylphenyl)(4-acetamidephenyl)methanone (1-1j) (38%)¹H NMR (300 MHz, DMSO-d₆) δ 13.21 (br s, 1H), 9.66 (br s, 1H), 7.88 (d,J=8.1 Hz, 2H), 7.44 (d, J=8.4 Hz, 1H), 6.56 (d, J=8.2 Hz, 1H), 6.50 (d,J=8.3 Hz, 2H), 6.10 (s, 1H), 2.09 (s, 3H), 2.02 (s, 3H).

(2,4-Dihydroxy-5-ethyl-3-methylphenyl)(4-hydroxyphenyl)methanone (1-1k)(42%) ¹H NMR (300 MHz, DMSO-d₆) δ 13.55 (s, 1H), 11.20 (br, 1H), 10.90(br, 1H), 7.44 (d, J=8.2 Hz, 2H), 7.11 (s, 1H), 6.99 (d, J=8.2 Hz, 2H),3.45 (q, J=7.9 Hz, 2H), 2.2 (s, 3H), 1.34 (t, J=8.0 Hz, 3H).

(2,4-Dihydroxy-3-ethylphenyl)(4-hydroxyphenyl)methanone (1-11) ¹H NMR(300 MHz, DMSO-d₆) δ 12.2 (s, 1H), 7.43 (d, J=8.3 Hz, 1H), 7.35 (d,J=8.4 Hz, 2H), 7.11 (d, J=8.2 Hz, 1H), 6.55 (d, J=8.4Hz, 2H), 2.65 (m,2H), 1.04 (t, J=7.8 Hz, 3H).

(2,4-Dihydroxy-5-methylphenyl)(4-hydroxyphenyl)methanone (1-1m) ¹H NMR(300 MHz, DMSO-d₆) δ 11.90 (s, 1H), 10.90-95 (br, 2H), 7.40 (d, J=8.3Hz, 2H), 7.33 (s, 1H), 7.11 (d, J=8.3 Hz, 2H), 6.33 (s, 1H), 2.05 (s,3H).

(2,4-Dihydroxy-5-flourophenyl)(3-fluoro-4-hydroxyphenyl)methanone (1-1n)¹H NMR (300 MHz, DMSO-d₆) δ 7.99 (m, 1H), 7.55-7.35 (m, 3H), 7.05 (m,1H), 6.55 (s, 1H).

(5-chloro-2,4-Dihydroxyphenyl)(3-fluoro-4-hydroxyphenyl)methanone (1-1o)¹H NMR (300 MHz, DMSO-d₆) δ 11.11 (s, 1H), 7.89 (m, 1H), 7.55-45 (m,2H), 7.11 (s, 1H), 6.5 (s, 1H).

(2,4-Dihydroxy-3-methylphenyl)(3-chloro-4-hydroxyphenyl)methanone (1-1p)¹H NMR (300 MHz, DMSO-d₆) δ 12.91 (s, 1H), 11.11 (br, 1H), 10.65 (br,1H), 7.90 (s, 1H), 7.55 (d, J=8.2 Hz, 1H), 7.36 (d, J=8.3 Hz, 1H), 7.11(d, J=8.3 Hz, 1H), 6.23 (d, J=8.2Hz, 1H) 2.05 (s, 3H).

(2,4-Dihydroxy-5-ethyl-3-methylphenyl)(3-fluoro-4-hydroxyphenyl)methanone(1-1q) (42%) ¹H NMR (300 MHz, DMSO-d₆) δ 13.55 (s, 1H), 11.20 (br, 1H),10.90 (br, 1H), 7.55-7.45 (m, 2H), 7.11 (brs, 1H), 7.01 (s, 1H), 3.45(q, J =7.9 Hz, 2H), 2.2 (s, 3H), 1.34 (t, J=8.0 Hz, 3H).

(2,4-Dihydroxy-5-ethyl-3-methylphenyl)(3-methyl-4-hydroxyphenyl)methanone(1-1r) (41%) ¹H NMR (300 MHz, DMSO-d₆) δ 9.55 (s, 1H), 8.20 (br, 1H),7.90 (br, 1H), 6.65 (d, J=7.1Hz, 1H), 6.60 (dd, J=7.1, 2.1 Hz, 1H), 6.45(s, 1H), 6.35 (d, J=2.1 Hz, 1H), 3.15 (q, J=7.9 Hz, 2H), 2.2 (s, 3H),1.14 (t, J=8.0 Hz, 3H).

(2,4-Dihydroxy-5-ethyl-3-methylphenyl)(2-methyl-4-hydroxyphenyl)methanone(1-1s) (32%) ¹H NMR (300 MHz, DMSO-d₆) δ 9.59 (s, 1H), 8.60 (br, 1H),7.95 (br, 1H), 6.68 (d, J=7.1 Hz, 1H), 6.60 (s, 1H), 6.56 (d, J=7.Hz,1H), 6.35 (dd, J=6.9, 2.1 Hz, 1H), 3.25 (q, J=7.8 Hz, 2H), 2.2 (s, 3H),1.24 (t, J=8.0 Hz, 3H).

(2,4-Dihydroxy-5-ethyl-3-methylphenyl)(2-fluoro-4-hydroxyphenyl)methanone(1-10 (38%) ¹H NMR (300 MHz, DMSO-d₆) δ 10.9 (s, 1H), 9.16 (br, 1H),7.95 (br, 1H), 6.78 (dd J=6.9, 6.2 Hz, 1H), 6.62 (brd, J=7.1 Hz, 1H),6.56 (s, 1H), 6.45 (brd, J=6.9 Hz, 1H), 3.28 (q, J=7.8 Hz, 2H), 2.2 (s,3H), 1.14 (t, J=8.0 Hz, 3H).

Step 2.3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2a)

(2,4-Dihydroxy-3-methylphenyl)(4-hydroxyphenyl)methanone (36.8 g, 1 eq.)and 3,5-dimethoxy-4-hydroxyphenylacetic acid (32 g, 1 eq.), was added toacetic anhydride (110 mL), with stirring the diisopropylethylamine (64.4g, 4.5 eq.) was then added over 5 minutes. The reaction was heated to130-140° C. for 18 hrs then cooled to room temperature and poured ontowater (750 mL). The aqeous was extracted with DCM (2×750 mL), washedwith water (500 mL), brine (300 mL), dried over MgSO₄, then stripped toafford a dark brown sticky solid. The crude material was treated withEtOAc (200 mL), stirred, heated to reflux and cooled, solid filtered offwashed with ice cold EtOAc (50 mL) to give a pale yellow solid (66 g).The solid was treated 2 x EtOAc (100 mL) stirring at r.t. for 30 min,filtered to give a white solid (62 g, 76%). ¹H NMR (300 MHz, CDCl₃) δ7.18-7.07 (m, 5H), 6.93 (d, J=8.3 Hz, 1H), 6.37 (s, 2H), 3.62 (s, 6H),2.38 (s, 3H), 2.36 (s, 3H), 2.30 (s, 3H), 2.28 (s, 3H).

Other analogues prepared via this method:

4-(7-Acetoxy-8-methyl-2-oxo-3-(3,4,5-trimethoxyphenyl)-2H-chromen-4-yl)phenylacetate (1-2b) (61%). ¹H NMR (300 MHz, CDCl₃) δ 7.17-7.06 (m, 5H), 6.91(d, J=8.3 Hz, 1H), 6.34 (s, 2H), 3.80 (s, 3H), 3.65 (s, 6H), 2.38 (s,3H), 2.36 (s, 3H), 2.30 (s, 3H).

3-(4-Acetoxy-3,5-di-tert-butylphenyl)-4-(4-acetoxyphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2c) (21%). ¹H NMR (300 MHz, CDCl₃) δ 7.20-7.00 (m, 7H),6.94-6.86 (m, 2H), 2.36 (s, 3H), 2.34 (s, 3H), 2.29 (s, 3H), 1.44 (s,9H), 1.09 (s, 9H).

4-(7-Acetoxy-8-methyl-2-oxo-3-(3,4,5-trifluorophenyl)-2H-chromen-4-yl)phenylacetate (1-2d) (20%). ¹H NMR (300 MHz, CDCl₃) δ 7.18-7.08 (m, 5H), 7.01(d, J=8.8 Hz, 1H), 6.80-6.71 (m, 2H), 2.38 (s, 3H), 2.36 (s, 3H), 2.33(s, 3H).

4-(7-Acetoxy-2-oxo-3-(3,4,5-trifluorophenyl)-2H-chromen-4-yl)-2-fluorophenylacetate (1-2e) (76%). ¹H NMR (300 MHz, DMSO-d₆) δ 7.57-7.29 (m, 4H),7.21-7.10 (m, 4H), 2.31 (s, 6H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-fluorophenyl)-2-oxo-2H-chromen-7-ylacetate (1-2f) (68%). ¹H NMR (300 MHz, CDCl₃) δ 7.31-7.20 (m, 2H),7.17-7.10 (m, 1H), 7.07-6.98 (m, 2H), 6.94-6.88 (m, 1H), 6.38 (s, 2H),3.64 (s, 6H), 2.36 (s, 3H), 2.34 (s, 3H), 2.29 (s, 3H).

4-(7-Acetoxy-2-oxo-3-(3,4,5-trimethoxyphenyl)-2H-chromen-4-yl)-2-fluorophenylacetate (1-2g) (50%). ¹H NMR (300 MHz, CDCl₃) δ 7.32-7.22 (m, 2H),7.18-7.05 (m, 1H), 7.08-6.90 (m, 3H), 6.33 (s, 2H), 3.72 (s, 3H), 3.69(s, 6H), 2.38 (s, 6H).

4-(4-Acetoxy-3-fluorophenyl)-8-methyl-2-oxo-3-(3,4,5-trifluorophenyl)-2H-chromen-7-ylacetate (1-2h) (49%). ¹H NMR (300 MHz, CDCl₃) δ 7.37-7.05 (m, 4H),7.03-6.88 (m, 2H), 6.81-6.70 (m, 1H), 6.38 (s, 1H), 2.36 (bs, 9H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-fluorophenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2i) (46%). ¹H NMR (300 MHz, CDCl₃) δ 7.18-6.87 (m, 5H), 6.39(s, 2H), 3.66 (s, 6H), 2.38 (s, 3H), 2.36 (s, 3H), 2.33 (s, 3H), 2.29(s, 3H).

4-(4-Acetoxy-3-fluorophenyl)-8-methyl-2-oxo-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ylacetate (1-2j) (49%). ¹H NMR (300 MHz, CDCl₃) δ 7.16-6.89 (m, 5H), 6.34(s, 2H), 3.82 (s, 3H), 3.68 (s, 6H), 2.38 (s, 3H), 2.34 (s, 3H), 2.31(s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-methoxy-3,5-dimethylphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2k) (30%). ¹H NMR (300 MHz, CDCl₃) δ 7.20 (d, J=8.4 Hz, 1H),6.92 (d, J=8.4 Hz, 1H), 6.77 (s, 2H), 6.42 (s, 2H), 3.72 (s, 3H), 3.61(s, 6H), 2.38 (s, 3H), 2.36 (s, 3H), 2.30 (s, 3H), 2.20 (s, 6H).

4-(4-Methoxy-3,5-dimethylphenyl)-8-methyl-2-oxo-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ylacetate (1-2l) (34%). ¹H NMR (300 MHz, CDCl₃) δ 7.15 (d, J=8.7 Hz, 1H),6.90 (d, J=8.7 Hz, 1H), 6.76 (s, 2H), 6.38 (s, 2H), 3.80 (s, 3H), 3.71(s, 3H), 3.66 (s, 6H), 2.39 (s, 3H), 2.37 (s, 3H), 2.30 (s, 3H), 2.20(s, 6H).

4-(4-Acetoxy-3,5-difluorophenyl)-3-(4-acetoxy-3,5-dimethoxyphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2m) (30%). ¹H NMR (300 MHz, CDCl₃) δ 7.03-6.90 (m, 3H),6.84-6.76 (m, 1H), 6.47 (s, 2H), 3.73 (s, 6H), 2.39 (s, 3H), 2.37 (s,3H), 2.34 (s, 3H), 2.28 (s, 3H).

4-(4-Acetoxy-3,5-difluorophenyl)-8-methyl-2-oxo-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ylacetate (1-2n) (22%). ¹H NMR (300 MHz, CDCl₃) δ 7.03-6.77 (m, 4H), 6.40(s, 2H), 3.77 (s, 3H), 3.71 (s, 6H), 2.38 (s, 3H), 2.36 (s, 3H), 2.34(s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(3-fluoro-4-acetoxyphenyl)-8-propyl-2-oxo-2H-chromen-7-ylacetate (1-2o) (34%). ¹H NMR (300 MHz, CDCl₃) δ 7.18 (d, J=8.2 Hz, 2H),7.15-09 (m, 2H), 6.87 (d, J=8.2 Hz, 2H), 6.82 (d, J=8.5 Hz, 1H), 6.36(s, 2H), 3.73 (s, 6H), 2.75 (t, J=7.6Hz, 2H), 2.13 (s, 3H), 2.10 (s,3H), 2.05 (s, 3H), 1.65 (m, 1H), 1.06 (t, J=7.6 Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(3-fluoro-4-acetoxyphenyl)-6-ethyl-2-oxo-2H-chromen-7-ylacetate (1-2p) (34%). ¹H NMR (300 MHz, CDCl₃) δ 7.18 (s, 1H), 7.16 (m,1H), 7.08 (s, 1H), 7.04 (dd, J=8.2, 1.5 Hz, 1H), 6.95 (dd, J=8.3, 2.5Hz, 1H), 6.35 (s, 2H), 3.56 (s, 6H), 2.56 (q, J=7.6 Hz, 2H), 2.12 (s,3H), 2.10 (s, 3H), 2.09 (s, 3H), 1.04 (t, J=7.7Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(3,4-methylenedioxyphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2q) (75%). ¹H NMR (300 MHz, CDCl₃) δ 7.20 (d, J=8.3 Hz, 1H),6.96 (d, J=8.2 Hz, 1H), 6.75 (d, J=8.2 Hz, 1H), 6.56 (d, J=8.3 Hz, 1H),6.51 (s, 1H), 6.34 (s, 2H), 5.96 (s, 1H), 5.91 (s, 1H), 3.58 (s, 6H),2.25 (s, 3H), 2.20 (s, 3H), 1.65 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-nitrophenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2r) (25%). ¹H NMR (300 MHz, CDCl₃) δ 8.25 (d, J=8.6 Hz, 2H),7.35 (d, J=8.4 Hz, 2H), 6.96 (m, 2H), 6.34 (s, 2H), 3.67 (s, 6H), 2.25(s, 3H), 2.21 (s, 3H), 1.89 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-ethylaminophenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2s) (45%). ¹H NMR (300 MHz, CDCl₃) δ 7.51 (d, J=8.2 Hz, 2H),7.17 (d, J=8.2 Hz, 1H), 7.09 (d, J=8.2 Hz, 2H), 6.87 (d, J=8.3 Hz, 1H),6.43 (s, 2H), 3.61 (s, 6H), 2.42 (s, 3H), 2.25 (s, 3H), 2.12 (s, 3H),1.96 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2t) (25%). ¹H NMR (300 MHz, CDCl₃) δ 7.18 (d, J=8.2 Hz, 2H),6.96 (s, 1H), 6.87 (d, J=8.3 Hz, 2H), 6.35 (s, 2H), 3.61 (s, 6H), 2.32(q, J=7.2 Hz, 2H), 2.25 (s, 3H), 2.21 (s, 3H), 2.16 (s, 3H), 1.95 (s,3H), 1.05 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-8-ethyl-2-oxo-2H-chromen-7-ylacetate (1-2u) (45%). ¹H NMR (300 MHz, CDCl₃) δ 7.21 (d, J=8.2 Hz, 2H),7.10 (d, J=8.4Hz, 1H), 6.97 (d, J=8.3 Hz, 2H), 6.91 (d, J=8.4 Hz, 1H),6.41 (s, 2H), 3.61 (s, 6H), 2.81 (q, J=7.2 Hz, 2H), 2.25 (s, 3H), 2.21(s, 3H), 2.18 (s, 3H), 1.25 (t, J =7.1Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-6-methyl-2-oxo-2H-chromen-7-ylacetate (1-2v) (55%). ¹H NMR (300 MHz, CDCl₃) δ 7.21 (d, J=8.2 Hz, 2H),7.18 (d, J=8.2 Hz, 2H), 7.07 (m, 1H), 6.88 (m,1H), 6.34 (s, 2H), 3.61(s, 6H), 2.28 (s, 3H), 2.21 (s, 3H), 2.18 (s, 3H), 1.96 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-fluorophenyl)-5-fluoro-2-oxo-2H-chromen-7-ylacetate (1-2w) (15%). ¹H NMR (300 MHz, CDCl₃) δ 7.07-7.02 (m, 2H),6.96-86 (m, 1H), 6.58 (s, 1H), 6.50 (s, 1H), 6.36 (s, 2H), 3.61 (s, 6H),2.23 (s, 3H), 2.21 (s, 3H), 2.18 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-6-chloro-2-oxo-2H-chromen-7-ylacetate (1-2x) (45%). ¹H NMR (300 MHz, CDCl₃) δ 7.21 (m, 2H), 7.18 (dd,J=1.4, 1.2 Hz, 1H), 7.02 (dd, J=1.2, 8.1 Hz, 1H), 6.96 (dd, J=1.3, 8.6Hz, 1H), 6.41 (s, 2H), 3.61 (s, 6H), 2.45 (s, 3H), 2.35 (s, 3H), 2.21(s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-chlorophenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2y) (55%). ¹H NMR (300 MHz, CDCl₃) δ 7.31 (s, 1H), 7.10 (m,2H), 7.05-7.01 (m, 2H), 6.45 (s, 2H), 3.66 (s, 6H), 2.35 (s, 3H), 2.21(s, 3H), 2.18 (s, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-fluorophenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2z) (35%). ¹H NMR (300 MHz, CDCl₃) δ 7.07-7.02 (m, 2H),6.96-88 (m, 1H), 6.86 (s, 1H), 6.35 (s, 2H), 3.61 (s, 6H), 2.32 (q,J=7.2 Hz, 2H), 2.25 (s, 3H), 2.21 (s, 3H), 2.16 (s, 3H), 1.95 (s, 3H),1.05 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-3-methylphenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2aa) (38%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.5 Hz, 1H),6.65 (dd, J=7.1, 2.1 Hz, 1H), 6.45 (s, 1H), 6.35 (d, J=2.1 Hz, 1H), 5.98(s, 2H), 3.61 (s, 6H), 2.38 (q, J=7.2 Hz, 2H), 2.26 (s, 3H), 2.18 (s,3H), 2.16 (s, 3H), 1.95 (s, 3H), 1.05 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethylphenyl)-4-(4-acetoxy-3-methylphenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2bb) (38%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.5 Hz, 1H),6.65 (dd, J=7.1, 2.1 Hz, 1H), 6.45 (s, 1H), 6.35 (d, J=2.1 Hz, 1H), 6.23(s, 2H), 2.31 (q, J=7.2 Hz, 2H), 2.23 (s, 3H), 2.15 (s, 3H), 2.14 (s,3H), 2.11 (s, 6H), 1.98 (s, 3H), 1.15 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxy-2-methylphenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2cc) (36%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.1 Hz, 1H),6.60 (s, 1H), 6.46 (d, J=7.Hz, 1H), 6.30 (dd, J=6.9, 2.1 Hz, 1H), 5.92(s, 2H), 3.65 (s, 6H), 2.33 (q, J=7.2 Hz, 2H), 2.2 (s, 3H), 2.18 (s,3H), 2.16 (s, 3H), 1.95 (s, 3H), 1.15 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethylphenyl)-4-(4-acetoxy-2-fluorophenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-2dd) (38%). ¹H NMR (300 MHz, CDCl₃) δ 6.88 (dd J=6.9, 6.5 Hz,1H), 6.66 (brd, J=7.0 Hz, 1H), 6.56(s, 1H), 6.45 (brd, J=6.5 Hz, 1H),2.31 (q, J=7.2 Hz, 2H), 2.29 (s, 3H), 2.18 (s, 3H), 2.14 (s, 3H), 2.12(s, 6H), 1.95 (s, 3H), 1.17 (t, J=7.2 Hz, 3H).

Step 3.3-(4-Hydroxy-3,5-dimethoxyphenyl)-4-(4-hydroxyphenyl)-8-methyl-2H-chromen-7-ol(1-3a)

3-(4-Acetoxy-3,5-dimethoxyphenyl)-4-(4-acetoxyphenyl)-8-methyl-2-oxo-2H-chromen-7-ylacetate (24 g, 1 eq), and THF (1500 mL) was added to a flask under N₂and cooled to 5° C. Borane dimethyl sulfide complex 2 M in THF (400 ml,18 eq) was added over 10 mins. The solution was stirred for 2 hours atthis temp then heated to 40 C o/n. The mixture was poured onto 2 M HCl(2000 mL) at <15° C., then extracted with EtOAc (2×1000 mL). Thecombined organics were washed with water (2×1000 mL), brine, dried(MgSO₄) then stripped to dryness affording crude (1-3a) as a stickyyellow solid. The material was purified by column chromatography elutingwith heptane to heptane/EtOAc 3:2. The product fractions were strippeddown to afford the title compound (9.5 g, 53%) as an orange solid. ¹HNMR (300 MHz, Acetone-d₆) δ 8.39 (bs, 2H), 7.14 (s, 1H), 6.98 (d, J=8.6Hz, 2H), 6.82 (d, J=8.6 Hz, 2H), 6.54 (d, J=7.9 Hz, 1H), 6.40 (d, J=7.9Hz, 1H), 6.35 (s, 2H), 5.07 (s, 2H), 3.61 (s, 6H), 2.12 (s, 3H).

Other analogues prepared by this method:

4-(4-Hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3b) (47%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.38 (bs, 2H), 6.98 (d,J=8.8 Hz, 2H), 6.81 (d, J=8.8 Hz, 2H), 6.53 (d, J=7.9 Hz, 1H), 6.43-6.35(m, 3H), 5.08 (s, 2H), 3.66 (s, 3H), 3.61 (s, 6H), 2.22 (s, 3H).

3-(3,5-Di-tert-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-8-methyl-2H-chromen-7-ol(1-3c) (36%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.36-8.29 (m, 2H),7.50-7.42 (m, 1H), 6.94-6.77 (m, 5H), 6.52 (d, J=7.9 Hz, 1H), 6.39 (d,J=7.9 Hz, 1H), 5.97 (s, 1H), 5.09 (s, 2H), 2.13 (s, 3H), 1.51 (s, 9H),1.30 (s, 9H).

4-(4-Hydroxyphenyl)-8-methyl-3-(3,4,5-trifluorophenyl)-2H-chromen-7-ol(1-3d) (41%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.52 (bs, 1H), 8.50 (bs,1H), 6.98 (d, J=8.3 Hz, 2H), 6.90-6.80 (m, 4H), 6.54 (d, J=7.9 Hz, 1H),6.47 (d, J=7.9 Hz, 1H), 5.05 (s, 2H), 2.12 (s, 3H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(3,4,5-trifluorophenyl)-2H-chromen-7-ol(1-3e) (34%).

¹H NMR (300 MHz, Acetone-d₆) δ 8.80 (bs, 1H), 8.66 (bs, 1H), 7.05-6.77(m, 5H), 6.74-6.66 (m, 1H), 6.45-6.34 (m, 2H), 5.03 (s, 2H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3f) (44%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.72 (bs, 1H), 8.57 (bs,1H), 7.20 (bs, 1H), 7.06-6.96 (m, 1H), 6.91-6.80 (m, 2H), 6.81-6.75 (m,1H), 6.45-6.37 (m, 4H), 5.08 (s, 2H), 3.63 (s, 6H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3g) (48%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.74 (bs, 1H), 8.59 (bs,1H), 7.04-6.80 (m, 3H), 6.84-6.82 (m, 1H), 6.48-6.37 (m, 4H), 5.08 (s,2H), 3.70 (s, 3H), 3.62 (s, 6H).

4-(3-Fluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trifluorophenyl)-2H-chromen-7-ol(1-3h) (48%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.80 (bs, 1H), 8.57 (bs,1H), 7.04-6.75 (m, 5H), 6.54 (d, J=8.2 Hz, 1H), 6.43 (d, J=8.2 Hz, 1H),5.06 (s, 2H), 2.12 (s, 3H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methyl-2H-chromen-7-ol(1-3i) (53%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.66 (bs, 1H), 8.37 (bs,1H), 7.19 (bs, 1H), 7.06-6.76 (m, 3H), 6.53 (d, J=8.5 Hz, 1H), 6.45-6.35(m, 3H), 5.07 (s, 2H), 3.63 (s, 6H), 2.17 (s, 3H).

4-(3-Fluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3j) (49%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.68 (bs, 1H), 8.49 (bs,1H), 7.04-6.77 (m, 3H), 6.53 (d, J=8.5 Hz, 1H), 6.48-6.36 (m, 3H), 5.07(s, 2H), 3.68 (s, 3H), 3.65 (s, 6H), 2.13 (s, 3H).

3-(4-Hydroxy-3,5-dimethoxyphenyl)-4-(4-methoxy-3,5-dimethylphenyl)-8-methyl-2H-chromen-7-ol(1-3k) (22%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.37 (bs, 1H), 7.21 (bs,1H), 6.32 (s, 2H), 6.49-6.34 (m, 4H), 5.08 (s, 2H), 3.71 (s, 3H), 3.60(s, 6H), 2.22 (s, 6H), 2.13 (s, 3H).

4-(4-Methoxy-3,5-dimethylphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3l) (15%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.41 (bs, 1H), 6.81 (s,2H), 6.49-6.36 (m, 4H), 5.08 (s, 2H), 3.73 (s, 3H), 3.66 (s, 3H), 3.61(s, 6H), 2.22 (s, 6H), 2.12 (s, 3H).

4-(3,5-Difluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methyl-2H-chromen-7-ol(1-3m) (47%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.86-6.74 (m, 2H),6.47-6.36 (m, 4H), 5.10 (s, 2H), 3.66 (s, 6H), 2.13 (s, 3H).

4-(3,5-Difluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3n) (55%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.86-6.75 (m, 2H),6.49-6.37 (m, 4H), 5.12 (s, 2H), 3.66 (s, 9H), 2.14 (s, 3H).

4-(3-fluoro-4-hydroxyphenyl)-8-propyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3o) (36%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.72 (s, 1H), 8.12 (s, 1H),7.05 (s, 1H), 7.01 (m, 1H), 6.95-78 (m, 2H), 6.48 (d, J=8.1 Hz, 2H),6.45 (d, J=8.1Hz, 2H), 6.41 (s, 2H), 5.02 (s, 2H), 3.71 (s, 6H), 2.65(m, 1H), 1.65 (m, 1H), 1.06 (t, J=7.1Hz, 3H).

4-(3-fluoro-4-hydroxyphenyl)-6-ethyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3p) (54%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.54 (s, 1H), 8.05 (s, 1H),7.29 (s, 1H), 7.05 (m, 1H), 6.78 (m, 1H), 6.66 (s, 1H), 6.45 (s, 1H),6.34 (s, 2H), 5.04 (s, 2H), 3.65 (s, 6H), 2.45 (m, 2H), 1.06 (t, J=7.1Hz, 3H).

3-(4-hydroxy-3,5-dimethoxyphenyl)-4-(3,4-methylenedioxyphenyl)-8-methyl-2H-chromen-7-ol(1-3q) (54%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.23 (s, 1H), 7.31 (s, 1H),6.82 (d, J=8.01 Hz, 1H), 6.66 (d, J=8.1 Hz, 1H), 6.61 (s, 1H), 6.50 (d,J=8.2 Hz, 1H), 6.42 (s, 2H), 6.40 (d, J=8.2 Hz, 1H), 6.04 (s, 2H), 5.11(s, 2H), 3.57 (s, 6H), 1.78 (s, 3H).

3-(4-hydroxy-3,5-dimethoxyphenyl)-4-(4-nitrophenyl)-8-methyl-2H-chromen-7-ol(1-3r) (24%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.23 (s, 1H), 8.23 (d,J=8.6 Hz, 2H), 7.45 (d, J=8.4 Hz, 2H), 7.25 (s, 1H), 6.38 (s, 2H), 6.32(s, 2H), 5.04 (s, 2H), 3.56 (s, 6H), 2.01 (s, 3H).

3-(4-hydroxy-3,5-dimethoxyphenyl)-4-(4-ethylaminophenyl)-8-methyl-2H-chromen-7-ol(1-3s) (21%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.23 (s, 1H), 7.22 (d,J=8.2 Hz, 1H), 6.97 (d, J=8.2 Hz, 2H), 6.66 (d, J=8.3 Hz, 2H), 6.34 (d,J=8.2 Hz, 1H), 6.34 (s, 2H), 5.04 (s, 2H), 3.45 (s, 6H), 3.05 (m, 2H),1.06 (t, J=7.6 Hz, 3H).

4-(4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3t) (31%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.67 (s, 1H), 7.45 (s, 1H),7.05 (d, J=8.3 Hz, 2H), 6.98 (d, J=8.3 Hz, 2H), 6.65 (s, 1H), 6.45 (s,2H), 5.08 (s, 2H), 3.56 (s, 6H), 2.55 (m, 2H), 2.05 (s, 3H), 1.07 (t,J=7.2 Hz, 3H).

4-(4-hydroxyphenyl)-8-ethyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3u) (61%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.34 (s, 1H), 8.11 (s, 1H),7.26 (s, 1H), 7.01 (m, 2H), 6.76 (m, 2H), 6.56 (d, J=8.1 Hz, 1H), 6.50(d, J=8.2 Hz, 1H), 6.45 (s, 2H), 5.10 (s, 2H), 3.47 (s, 6H), 2.65 (m,2H), 1.06 (t, J=7.5 Hz, 3H).

4-(4-hydroxyphenyl)-6-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3v) (68%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.88 (s, 1H), 8.23 (s, 1H),7.33 (d, J=3 Hz, 1H), 7.05 (m, 2H), 6.78 (m, 2H), 6.65 (s, 1H), 6.34 (s,2H), 5.11 (s, 2H), 3.56 (s, 6H), 2.07 (s, 3H).

4-(3-fluoro-4-hydroxyphenyl)-5-fluoro-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3w) (21%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.12 (s, 1H), 7.23 (s, 1H),6.88-76 (m, 3H), 6.50 (s, 1H), 6.45 (s, 2H), 6.05 (d, J=8.2 Hz, 1H),4.89 (s, 2H), 3.56 (s, 6H).

6-chloro-4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-trimethoxyphenyl)-2H-chromen-7-ol(1-3x) (21%). ¹H NMR (300 MHz, Acetone-d₆) δ 7.32 (m, 1H), 7.16-09 (m,2H), 6.94 (s, 1H), 6.59 (s, 1H), 6.39 (s, 2H), 5.10 (s, 2H), 3.65 (s,6H).

4-(3-chloro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methyl-2H-chromen-7-ol(1-3y) (41%). ¹H NMR (300 MHz, Acetone-d₆) δ 7.11 (d, J=1.6 Hz, 1H),6.96 (d, J=8.1 Hz, 1H), 6.88 (dd, J=1.2, 8.2 Hz, 1H), 6.55 (d, J=8.2 Hz,1H), 6.45 (d, J=8.1 Hz, 1H), 6.42 (s, 2H), 5.11 (s, 2H), 3.65 (s, 6H),2.05 (s, 3H).

4-(3-fluoro-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3z) (41%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.77 (s, 1H), 7.49 (s, 1H),7.15 (m, 2H), 6.98 (brs, 1H), 6.65 (s, 1H), 6.45 (s, 2H), 5.08 (s, 2H),3.56 (s, 6H), 2.55 (m, 2H), 2.05 (s, 3H), 1.07 (t, J=7.2 Hz, 3H).

4-(3-methyl-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3aa) (38%). ¹H NMR (300 MHz, CDCl₃) δ 8.22 (br, 2H), 7.66 (s, 1H),6.62 (d, J=7.1 Hz, 1H), 6.55 (dd, J=7.1, 2.3 Hz, 1H), 6.41 (s, 1H), 6.38(d, J=2.5 Hz, 1H), 5.95 (s, 2H), 3.51 (s, 6H), 2.32 (q, J=7.2 Hz, 2H),2.21 (s, 3H), 2.18 (s, 3H), 2.14 (s, 3H), 1.92 (s, 3H), 1.05 (t, J=7.2Hz, 3H).

4-(3-fluoro-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(1-3bb) (38%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.5 Hz, 1H), 6.65(dd, J=7.1, 2.1 Hz, 1H), 6.45 (s, 1H), 6.35 (d, J=2.1 Hz, 1H), 6.23 (s,2H), 2.31 (q, J=7.2 Hz, 2H), 2.23 (s, 3H), 2.15 (s, 3H), 2.14 (s, 3H),2.11 (s, 6H), 1.98 (s, 3H), 1.15 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethylphenyl)-4-(4-acetoxy-3-methylphenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-3cc) (36%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.1 Hz, 1H),6.60 (s, 1H), 6.46 (d, J=7 Hz, 1H), 6.30 (dd, J=6.9, 2.1 Hz, 1H), 5.92(s, 2H), 3.65 (s, 6H), 2.33 (q, J=7.2Hz, 2H), 2.2 (s, 3H), 2.18 (s, 3H),2.16 (s, 3H), 1.95 (s, 3H), 1.15 (t, J=7.2 Hz, 3H).

3-(4-Acetoxy-3,5-dimethylphenyl)-4-(4-acetoxy-2-fluorophenyl)-6-ethyl-8-methyl-2-oxo-2H-chromen-7-ylacetate (1-3dd) (38%). ¹H NMR (300 MHz, CDCl₃) δ 9.08 (br 1H), 8.65 (s,1H), 8.22 (br 1H), 6.81 (dd J=6.6, 6.3 Hz, 1H), 6.62 (brd, J=7.0 Hz,1H), 6.46 (s, 1H), 6.35 (brd, J=6.5 Hz, 1H), 2.31 (q, J=7.2 Hz, 2H),2.29 (s, 3H), 2.18 (s, 3H), 2.14 (s, 3H), 2.12 (s, 6H), 1.95 (s, 3H),1.17 (t, J=7.2 Hz, 3H).

Step 4.3-(4-Hydroxy-3,5-dimethoxyphenyl)-4-(4-hydroxyphenyl)-8-methylchroman-7-ol(Compound 2) (1-4a)

3-(4-Hydroxy-3,5-dimethoxyphenyl)-4-(4-hydroxyphenyl)-8-methyl-2H-chromen-7-ol(4.8 g, 1 eq), IMS (500 mL) and Pd/C 10% type 338 paste (3.0 g) wasadded to a hydrogenator and filled with H₂ 2.5 bar. The reaction wasleft at 40° C. overnight and showed complete conversion. The catalystwas filtered off and the filtrates stripped to dryness. Three equalbatches were blended and dried to afford 12.6 g (88%) of Compound 2 asan off-white solid. ¹H NMR (300 MHz, Acetone-d₆) δ 6.65-6.51 (m, 5H),6.40 (d, J=7.9 Hz, 1H), 6.04 (s, 2H), 4.44-4.35 (m, 1H), 4.25-4.15 (m,2H), 3.64 (s, 6H), 3.46-3.37 (m, 1H), 2.15 (s, 3H).

Other compounds of formula (I) prepared by this method:

4-(4-Hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)chroman-7-ol(Compound 1) (1-4b) (99%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.63-6.49 (m,5H), 6.36 (d, J=7.9 Hz, 1H), 6.04 (s, 2H), 4.46-4.36 (m, 1H), 4.25-4.17(m, 2H), 3.68 (s, 3H), 3.63 (s, 6H), 3.49-3.40 (m, 1H), 2.15 (s, 3H).

3-(3,5-Di-tert-butyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)-8-methylchroman-7-ol(Compound 3) (1-4c) (33%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.10 (bs 1H),8.05 (bs, 1H) 7.28-7.20 (m, 1H), 6.63-6.52 (m, 3H), 6.43-6.36 (m, 2H),6.04 (s, 2H), 4.47-4.35 (m, 1H), 4.24-4.09 (m, 2H), 3.64 (s, 6H),3.78-3.66 (m, 1H), 2.15 (s, 3H), 1.45 (s, 9H), 1.32 (s, 9H).

4-(4-Hydroxyphenyl)-8-methyl-3-(3,4,5-trifluorophenyl)chroman-7-ol(Compound 4) (1-4d) (95%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.67-6.52 (m,7H), 6.42 (d, J=7.8 Hz, 1H), 4.48-4.40 (m, 1H), 4.35-4.26 (m, 2H),3.64-3.55 (m, 1H), 2.15 (s, 3H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(3,4,5-trifluorophenyl)chroman-7-ol(Compound 5) (1-4e) (50%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.84-6.65 (m,4H), 6.49-6.30 (m, 4H), 4.48-4.18 (m, 3H), 3.67-3.56 (m, 1H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)chroman-7-ol(Compound 6) (1-4f) (39%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.80-6.74 (m,2H), 6.44-6.32 (m, 4H), 6.08 (s, 2H), 4.41-4.33 (m, 1H), 4.24-4.12 (m,2H), 3.66 (s, 6H), 3.52-3.38 (m, 1H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(3,4,5-trimethoxyphenyl)chroman-7-ol(Compound 7) (1-4g) (22%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.80-6.72 (m,2H), 6.48-6.33 (m, 4H), 6.11 (s, 2H), 4.44-4.35 (m, 1H), 4.25-4.14 (m,2H), 3.70 (s, 3H), 3.64 (s, 6H), 3.52-3.45 (m, 1H).

4-(3-Fluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trifluorophenyl)chroman-7-ol(Compound 8) (1-4h) (50%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.81-6.65 (m,3H), 6.60 (d, J=8.6 Hz, 1H), 6.49-6.40 (m, 2H), 6.39-6.30 (m, 1H),4.50-4.42 (m, 1H), 4.38-4.30 (m, 2H), 3.66-3.55 (m, 1H), 2.16 (s, 3H).

4-(3-Fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 9) (1-41) (60%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.78-6.70 (m,1H), 6.60 (d, J=8.2 Hz, 1H), 6.46-6.32 (m, 3H), 6.07 (s, 2H), 4.45-4.35(m, 1H), 4.28-4.17 (m, 2H), 3.65 (s, 6H), 3.49-3.41 (m, 1H), 2.20 (s,3H).

4-(3-Fluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)chroman-7-ol(Compound 10) (1-4j) (44%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.80-6.71 (m,1H), 6.60 (d, J=8.2 Hz, 1H), 6.46-6.32 (m, 4H), 6.10 (s, 2H), 4.48-4.38(m, 1H), 4.31-4.22 (m, 2H), 3.69 (s, 3H), 3.65 (s, 6H), 3.53-3.41 (m,1H), 2.17 (s, 3H).

3-(4-Hydroxy-3,5-dimethoxyphenyl)-4-(4-methoxy-3,5-dimethylphenyl)-8-methylchroman-7-ol(Compound 11) (1-4k) (83%). ¹H NMR (300 MHz, DMSO-d₆) δ 6.52 (d, J=8.5Hz, 1H), 6.33 (d, J=8.5 Hz, 1H), 6.25 (s, 2H), 5.91 (s, 2H), 4.34-4.24(m, 1H), 4.18-4.05 (m, 2H), 3.57 (s, 3H), 3.50 (s, 6H), 3.48-3.33 (m,1H), 2.05 (s, 3H), 2.03 (s, 6H).

4-(4-Methoxy-3,5-dimethylphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)chroman-7-ol(Compound 12) (1-41) (99%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.58 (d,J=8.8 Hz, 1H), 6.42 (d, J=8.8 Hz, 1H), 6.33 (s, 2H), 6.05 (s, 2H),4.52-4.37 (m, 1H), 4.25-4.12 (m, 2H), 3.68 (s, 3H), 3.65 (s, 3H), 3.11(s, 6H), 3.50-3.39 (m, 1H), 2.15 (s, 3H), 2.07 (s, 6H).

4-(2,3-Difluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 13) (1-4m) (60%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.73-6.68 (m,1H), 6.64-6.57 (m, 1H), 6.55-6.49 (m, 1H), 6.42 (d, J=9.6 Hz, 1H), 6.08(s, 2H), 4.59-4.55 (m, 1H), 4.46-4.36 (m, 1H), 4.25-4.21 (m, 1H), 3.63(s, 6H), 3.53-3.47 (m, 1H), 2.14 (s, 3H).

4-(2,3-Difluoro-4-hydroxyphenyl)-8-methyl-3-(3,4,5-trimethoxyphenyl)chroman-7-ol(Compound 14) (1-4n) (66%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.74-6.68 (m,1H), 6.60 (d, J=9.5 Hz, 1H), 6.55-6.47 (m, 1H), 6.44 (d, J=9.5 Hz, 1H),6.13 (s, 2H), 4.61-4.57 (m, 1H), 4.48-4.36 (m, 1H), 4.29-4.22 (m, 1H),3.67 (s, 3H), 3.64 (s, 6H), 3.58-3.48 (m, 1H), 2.14 (s, 3H).

4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-propylchroman-7-ol(Compound 16) (1-4o) (80%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.76 (m, 1H),6.65 (d, J=8.1 Hz, 1H), 6.45-33 (m, 3H), 6.05 (s, 2H), 4.44 (m, 1H),4.27 (m, 1H), 3.56 (s, 6H), 3.45 (m, 1H), 2.65 (m, 2H), 1.67 (m, 2H),1.07 (t, J=7.1 Hz, 3H).

4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-ethylchroman-7-ol(Compound 18) (1-4p) (80%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.76 (m, 1H),6.66 (s, 1H), 6.56-38 (m, 3H), 6.05 (s, 2H), 4.45 (m, 1H), 4.12 (m, 1H),3.55 (s, 6H), 3.45 (m, 1H), 2.51 (m, 2H), 1.05 (t, J=7.1 Hz, 3H).

4-(3,4-methylenedioxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 32) (1-4q) (80%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.08 (s, 1H),7.01 (s, 1H), 6.71 (m, 2H), 6.55 (d, J=8.2 Hz, 1H), 6.23 (d, J=8.1 Hz,2H), 6.06 (s, 2H), 4.47 (m, 1H), 4.18 (m, 1H), 3.65 (s, 6H), 3.46 (m,1H), 2.05 (s, 3H).

4-(4-aminophenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 21) (1-4r) (70%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.67(m, 1H),6.45-33 (m, 5H), 6.09 (s, 2H), 4.47 (m, 1H), 4.13 (m, 1H), 3.64 (s, 6H),3.35 (m, 1H), 2.06 (s, 3H).

4-(4-ethylaminophenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 22) (1-4s) (78%). ¹H NMR (300 MHz, Acetone-d₆) δ6.65 (m, 1H),6.51-39 (m, 5H), 6.01 (s, 2H), 4.65 (m, 1H), 4.45 (m, 1H), 4.40 (m, 1H),3.65 (s, 6H), 3.45 (m, 1H), 3.11 (m, 2H), 2.06 (s, 3H), 1.32 (t, J=7.1Hz, 3H).

4-(4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-ethyl-8-methylchroman-7-ol(Compound 33) (1-4t) (80%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.75 (m, 1H),6.61 (s, 1H), 6.45 (m, 3H), 6.01 (s, 2H), 4.45 (m, 1H), 4.23 (m, 2H),3.65 (s, 6H), 3.45 (m, 1H), 2.55 (m, 2H), 2.01 (s, 3H), 1.07 (t, J=7.1Hz, 3H).

4-(4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-ethylchroman-7-ol(Compound 34) (1-4u) (86%). ¹H NMR (300 MHz, Acetone-d₆) δ6.72 (m, 1H),6.56 (d, J=8.2 Hz, 1H), 6.50-33 (m, 4H), 6.01 (s, 2H), 4.51 (m, 1H),4.32 (m, 2H), 3.65 (s, 6H), 3.45 (m, 1H), 2.65 (m, 2H), 1.06 (t, J=7.1Hz, 3H).

4-(4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-methylchroman-7-ol(Compound 35) (1-4v) (96%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.67 (m, 1H),6.56 (s, 1H), 6.45-32 (m, 4H), 6.01 (s, 2H), 4.45 (m, 1H), 4.32 (m, 2H),3.67 (s, 6H), 3.45 (m, 1H), 2.06 (s, 3H).

4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-5-fluorochroman-7-ol(Compound 19) (1-4w) (66%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.67 (m, 1H),6.45 (m, 2H), 6.25 (m, 1H), 6.18 (m, 1H), 6.01 (s, 2H), 4.50 (m, 1H),4.35 (m, 1H), 4.27 (m, 1H), 3.67 (s, 6H), 3.45 (m, 1H).

4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-chlorochroman-7-ol(Compound 20) (1-4x) (56%). ¹H NMR (300 MHz, Acetone-d₆) δ 8.16 (s, 1H),7.89 (s, 1H), 7.21 (s, 1H), 6.96 (s, 1H), 6.75 (m, 1H), 6.60 (s, 1H),6.45 (m, 1H), 6.01 (s, 2H), 4.45 (m, 1H), 4.30 (m, 2H), 3.67 (s, 6H),3.45 (m, 1H).

4-(3-chloro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-8-methylchroman-7-ol(Compound 24) (1-4y) (66%). ¹H NMR (300 MHz, Acetone-d₆) δ8.1 (s, 1H),7.6 (s, 1H), 7.0 (s, 1H), 6.65-50 (m, 4H), 6.42 (d, J=8.2 Hz, 1H), 6.01(s, 2H), 4.41 (m, 1H), 4.35 (m, 2H), 3.64 (s, 6H), 3.46 (m, 1H).

4-(3-fluoro-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-ethyl-8-methylchroman-7-ol(Compound 36) (1-4z) (80%). ¹H NMR (300 MHz, Acetone-d₆) δ 6.75 (m, 1H),6.61 (s, 1H), 6.45 (m, 3H), 6.01 (s, 2H), 4.45 (m, 1H), 4.23 (m, 2H),3.65 (s, 6H), 3.45 (m, 1H), 2.55 (m, 2H), 2.01 (s, 3H), 1.07 (t, J=7.1Hz, 3H).

4-(3-methyl-4-hydroxyphenyl)-3-(4-hydroxy-3,5-dimethoxyphenyl)-6-ethyl-8-methylchroman-7-ol(Compound 37) (1-4aa) (88%). ¹H NMR (300 MHz, CDCl₃) δ 8.22 (br, 2H),7.66 (s, 1H), 6.62 (d, J=7.1 Hz, 1H), 6.55 (dd, J=7.1, 2.3 Hz, 1H), 6.41(s, 1H), 6.38 (d, J=2.5 Hz, 1H), 5.95 (s, 2H), 4.48 (m, 1H), 4.21 (m,2H), 3.61 (s, 6H), 3.45 (m, 1H), 2.55 (m, 2H), 2.01 (s, 3H), 1.07 (t,J=7.1 Hz, 3H).

4-(3-methyl-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethylphenyl)-2H-chromen-7-ol(compound 38) (1-4bb) (80%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.5Hz, 1H), 6.65 (dd, J=7.1, 2.1 Hz, 1H), 6.45 (s, 1H), 6.35 (d, J=2.1 Hz,1H), 6.23 (s, 2H), 4.45 (m, 1H), 4.23 (m, 2H), 3.45 (m, 1H), 2.55 (m,2H), 2.15 (s, 6H), 2.01 (s, 3H), 1.02 (t, J=7.1 Hz, 3H).

4-(2-methyl-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethoxyphenyl)-2H-chromen-7-ol(compound 39) (1-4cc) (76%). ¹H NMR (300 MHz, CDCl₃) δ 6.68 (d, J=7.1Hz, 1H), 6.60 (s, 1H), 6.46 (d, J=7 Hz, 1H), 6.30 (dd, J=6.9, 2.1 Hz,1H), 5.92 (s, 2H), 4.42 (m, 1H), 4.31 (m, 2H), 3.65 (s, 6H), 3.41 (m,1H), 2.51 (m, 2H), 2.11 (s, 3H), 1.01(t, J=7.1 Hz, 3H).

4-(2-fluoro-4-hydroxyphenyl)-6-ethyl-8-methyl-3-(4-hydroxy-3,5-dimethylphenyl)-2H-chromen-7-ol(compound 40) (1-4dd) (70%). ¹H NMR (300 MHz, CDCl₃) δ 9.1 (br 1H), 8.75(s, 1H), 7.22 (br 1H), 6.85 (dd J=6.6, 6.1 Hz, 1H), 6.58 (brd, J=7.3 Hz,1H), 6.42 (s, 1H), 6.25 (brd, J=6.1 Hz, 1H), 4.35 (m, 1H), 4.13 (m, 2H),3.35 (m, 1H), 2.45 (m, 2H), 2.18 (s, 6H), 2.11(s, 3H), 1.05 (t, J=7.1Hz,3H).

Enantiomers of compound 2 were prepared by chiral resolution on a normalphase Chiralcel OD-H, 30×250 mm, 5 micron column. Analysis of thecompound with lowest retention time on this column indicated thefollowing Optical Rotation properties:

Specific Optical Rotation[α]²⁵ ₅₈₉ +282.250° Solvent: METHANOLConcentration: 1.0%

The enantiomer with the longest retention time on this column had thefollowing Optical Rotation properties.

Specific Optical Rotation[α]² ₅₈₉ −277.00° Solvent: METHANOLConcentration: 1.0%

Enantiomers of compound 6 were prepared by chiral resolution on a normalphase Chiralcel OD-H, 30×250 mm, 5 micron column. Analysis of thecompound with lowest retention time (enantiomer 1) on this columnindicated the following Optical Rotation properties:

Specific Optical Rotation[α]²⁵ ₅₈₉ +238.835° Solvent: METHANOLConcentration: 0.1%

The enantiomer with the longest retention time (enantiomer 2) on thiscolumn had the following Optical Rotation properties:

Specific Optical Rotation[α]²⁵ ₅₈₉ −259.410° Solvent: METHANOLConcentration: 0.1%

Enantiomers of compound 9 were prepared by chiral resolution on a normalphase Chiralcel OD-H, 30×250 mm, 5 micron column. Analysis of thecompound with lowest retention time (enantiomer 1) on this columnindicated the following Optical Rotation properties:

Specific Optical Rotation[α]²⁵ ₅₈₉ +252.727° Solvent: METHANOLConcentration: 0.1%

The enantiomer with the longest retention time (enantiomer 2) on thiscolumn had the following Optical Rotation properties:

Specific Optical Rotation[α]²⁵ ₅₈₉ −281.900° Solvent: METHANOLConcentration: 0.1%

Example 2 In Vitro Testing

The anti-cancer activity of compound 2 (the racemic form and a purifiedeutomer and distomer) was assessed by XenTech in two glioblastomemultiforme patient-derived explants established from tumour biopsiesfollowing the methodology detailed. Primary cell cultures were obtainedfrom explanted and dissociated ODA14-RAV and GBM14-CHA xenografts. Cellswere thawed quickly in a 37° C. water bath. One vial of cells HO millioncells) was diluted into 10 mL of complete growth medium (F12/DMEMsupplemented with 8% foetal bovine serum, 100 μg/ml penicillin G sodium,100 μg/ml streptomycin sulfate). After centrifugation at 150×g for 5minutes the cell pellet was resuspended in complete growth medium andplated at a density of at least 140,000 cells/cm² in 75 cm² cell cultureflasks. Cells were maintained at 37° C. in a humidified atmosphere with5% CO₂ for at least one week. The cells were then harvested and seededin 96-well plates at a density of 2.5×10³ cells/well for cytotoxicityassays. Cells were incubated for 48 hrs at 37° C. prior to addition ofthe test compounds. Test compounds were added at desired finalconcentrations and further incubated for 72 hrs.

Cell viability was assessed prior to adding the test compounds (TO) and72 hrs after by measuring cellular ATP cell content using CellTiter-Glo®Luminescent Cell Viability Assay (Promega) according to themanufacturer's instructions.

ODA14 was designated as grade III (determined by histopathology)susceptible to TMZ when assessed in xenograft studies, p53 mutant, pTENwildtype and had amplified EGFR expression. GBM14 was designated as TMZresistant, p53 wt, pTEN mutant, EGFR wt. The GBM grade was not known.After 72 hrs exposure to compound 2, an IC₅₀ of 0.14 μM against GBM14and 48 μM against ODA14 was observed. The results are shown in FIG. 1.After 72 hrs exposure of the eutomer of compound 2 an IC₅₀ of 0.051 μMwas observed, whereas in contrast the distomer of compound 2 had an IC₅₀of 3.43 μM (see FIG. 2) against the GBM14-CHA cell line. These datademonstrate that the eutomer of compound 2 (the + enantiomer) is some2-3 fold more active against GBM14-CHA compared with the racemate ofcompound 2 and >60 fold more active than the distomer of compound 2 (the− enantiomer).

The enantiomers of compounds 6 and 9 were also assessed againstGBM14-CHA glioblastoma cell line using the methodology described above.The results are presented below in Table 1.

TABLE 1 IC₅₀ data for the racemate and chiral forms of compounds 6 and 9against glioblastoma cell line GBM14-CHA Compound Chiral Form IC₅₀ (□M)6 Racemate 0.19 Ent 1 0.069 Ent 2 28.3 9 Racemate 0.19 Ent 1 0.017 Ent 211.29

As was observed for compound 2, the eutomers of compound 6 and 9 weredramatically more active than the corresponding distomers.

The anti-proliferative activity of compound 2 was also assessed inmatched TMZ susceptible (D54-S and U87-S) or resistant (D54-R and U87-R)cell lines (Hong Kong University, Dr Gilberto Leung). The data confirmthat TMZ had reduced efficacy against TMZ-resistant subclones of bothU87 and D54 compared to their respective TMZ-sensitive subclones. Incontrast to TMZ, compound 2 and its eutomer demonstrated equipotentanti-proliferative activity against both the D54 and U87 GBM cell linesregardless of their TMZ resistance status. Two methodologies (SRB andMTT) were used to assess viability and both showed that compound 2 wasequally effective at suppressing GBM cell viability regardless of TMZresistance status. SRB tended to overestimate cytotoxicity compared toMTT. However, IC₅₀ values were below 0.36 μM regardless of methodology,cell line, and TMZ status when treated with compound 2. The IC₅₀ valuesof compound 2 therefore, are markedly lower than TMZ, even against TMZsensitive subclones. Compound 2 eutomer was also equipotent againstTMZ-resistant and -sensitive subclones, but the anti-cancer efficacy wasmore potent for the active enantiomer than the racemate. IC₅₀ valueswere below 0.065 μM regardless of cell line and TMZ status (see Table2).

TABLE 2 Cell viability of U87 and D54 TMZ resistant and sensitivesubclones after treatment with TMZ, compound 2, or compound 2 eutomer*Compound 2 TMZ Compound 2 Compound 2 (+enantiomer) Compound (SRB) (SRB)(MTT) (MTT) U87-sensitive 609.12 0.106 0.329 0.037 U87-resistant 1828.510.128 0.358 0.041 D54-sensitive 630.99 0.090 0.271 0.065 D54-resistant2755.76 0.092 0.215 0.065 *Cell viability (IC₅₀) at 72 hours posttreatment was measured by SRB or MTT (as indicated). IC₅₀ in μM.

The anti-proliferative activity of the eutomer of compound 9 (the +enantiomer) was also assessed and found to be equipotent againstTMZ-resistant and − sensitive subclones of both U87 and D54 and similarto the eutomer of compound 2, IC₅₀ values were below 0.065 μM regardlessof cell line and TMZ status.

The efficacy of the eutomers of compounds 9 and 36 was also testedagainst paediatric neuroblastoma cell lines. IC₅₀ values ranged from0.020 μM to 0.088 μM for the compound 9 eutomer and from 0.243 μM to0.698 μM for the compound 36 eutomer. (see Table 3). Two more paediatricneural cancers were assessed for sensitivity to the eutomer of compound9. In vitro studies also showed low micromolar to sub-micromolarefficacy against a DIPG cell line, and nanomolar efficacy againstmedulloblastoma cell lines (D283L=0.097 μM; 547L=0.063 μM; andD425L=0.101 μM). Together with the previous studies using GBM cell linesand PDX cultures, these results suggest that compound 9 has considerablepotency against a range of neural cancers including major childhoodcancers.

TABLE 3 Cytotoxicity of compound 9 and 36 eutomers againstneuroblastoma* Cpd 9 Cpd 36 P53 nMYC (+enantiomer) (+enantiomer) Cellline status status IC₅₀ (□m) IC₅₀ (□m) CHLA-20 wildtype not 0.061 0.243amplified CHP-134 wildtype amplified 0.020 0.698 CHLA-90 mutant not0.088 0.336 amplified SK-N-Be(2) mutant amplified 0.064 0.308 *Cellviability was assessed after 72 hours

The ability of compounds 1 to 14 to inhibit the proliferation of ovariancancer stem cells was established from patient-derived explants. Thelaboratory of Dr Gil Mor (Yale University) have identified two types ofepithelial ovarian cancer cells: Type I are chemoresistant, CD44+veepithelial ovarian cancer (EOC) cells and Type II are chemosensitiveCD44−ve EOC cells. Ovarian cancer stem cells were prepared as describedpreviously (Alvero et al., 2009). Cell proliferation was assessed usingthe Incucyte Kinetic Imaging System. The cytotoxic effect of thecompounds was assessed concurrently using the CellPlayer cytotoxicityassay using CellTox™ (Promega, Cat#: G8731). Monolayer cells weretrypsinised and plated in 96-well plates. After 24 hrs, once the cellshave attached, treatment was dispensed in RPMI with 10% FBS. Drugconcentrations used were: 0.001, 0.01, 0.1, 1, and 10 μg/ml. Anappropriate dilution of CellTox™ reagent (1:1000) was added to each wellafter adding the test compound. Culture plates were immediately placedin the Incucyte system and imaged every 2 hrs using the “Fluorescenceand Phase contrast” option on the Incucyte equipment. Growth curves werecalculated as a measure of cell confluence using an integratedconfluence algorithm as a surrogate for cell number to determineproliferation rate. The area under the curve calculated from the plot ofCsttTox Count/mm² over time was then used to calculate the IC₅₀. Induplicate experiments it was found that compound 2 was most potent atretarding the proliferation of ovarian cancer stem cells atconcentrations between 0.01-0.1 μg/ml for OCSC-1 and OCSC-2. Compounds6, 9 and 13 were also potent at inhibiting the proliferation of OCSC-2cells at concentrations between 0.1 and 1 μg/ml (Table 4). Compound 2also elicited a similar effect against F2 cells at log-fold higherconcentrations (0.1-1 μg/ml ). Where assessed, all other analoguesexhibited anti-proliferative activity of 1-10 μg/ml (see Table 4).

TABLE 4 Anti-cancer effect of a series of compounds against ovariancancer stem cells IC₅₀ Range (μM) Compound OCSC1 OCSC2 F2 1 1-10 1-10 NT2 0.1-0.01 0.1-0.01 0.1-1 3 >10 1-10 NT 4 1-10 1-10 NT 5 NT 1-10 NT 6 NT0.1-1   NT 7 NT >10 NT 8 NT 1-10 NT 9 NT 0.1-1   NT 10 NT 1-10 NT 11 NT1-10 NT 12 NT >10 NT 13 NT 0.1-1   NT 14 NT >10 NT NT = not tested

Confirmatory studies using Incucyte confluence studies that employed agreater number of concentrations demonstrated that compound 2 had anIC₅₀ of 0.052 μg/ml against OCSC2. This observation was furtherconfirmed using Cytotox green, a dye reagent which exploits thecompromised membrane integrity of a dead cell, with the reagent able tocross the membrane and bind to DNA thereby releasing a fluorescencesignal that can be quantified. The IC₅₀ for compound 2 using CellToxgreen was 0.051 μg/ml. These data demonstrate that compound 2 is ahighly active anti-cancer compound as assessed by two differentmethodologies. IC₅₀ values of 0.12 g/ml were also generated forcompounds 9 and 13 (see FIGS. 3 and 4).

The ability of selected compounds to inhibit the proliferation of cancercells representative of melanoma, non-small cell lung cancer, colorectalcancer, breast cancer (Estogen Receptor negative (ER−ve, TNBC—ER−ve,Progesterone Receptor negative and negative for EGFR amplification),prostate cancer, liver cancer, ovarian cancer, pancreatic cancer andbrain cancer was studied. A pre-determined number of cells as calculatedfrom cell growth assays for each of the cell lines employed were seededinto their respective culture mediums (using ATCC cultureparameters—http://www.atcc.org) and cultured for 24 hrs at 37° C. and 5%CO₂ in 96-well culture plates. Once attached, each cell line was thenexposed to various concentrations of each respective analogue (30, 3,0.3 and 0.03 μM), cultured for a further 72 hrs and exposed tocell-titre luminescent reagent (100 μ/well) for a further 30 mins).Luminescence was captured using an EnVision multilabel reader and thedata for each analogue concentration compared against control. Semi-logplots of Percent of Control versus concentration were prepared and IC₅₀determined using linear regression analysis. The data are presented inTables 5 and 6. In Table 6, compounds Comp 1, Comp 2 and Comp 3 arecomparative compounds having the following structures:

TABLE 5 Assessment of a series of compounds for their ability to retardthe proliferation of a range of somatic cancer cells IC₅₀ (μM) BreastLung Liver Colorectal Melanoma Prostate MDA- (NSCLC) Hep Compound HT-29SK-Mel-28 PC3 DU145 MCF-7 MB-231 A549 G2 1 11 >30 >30 >30 >3013.7 >30 >30 2 8.2 1.4 1.49 0.08 13.6 0.8 0.04 1.9 3 7.5 >30 >30 15.126.7 7.5 11.8 >30 4 4.1 >30 >30 4.5 >30 9.9 6.9 >30 56.6 >30 >30 >30 >30 21.8 8.4 >30 6 8.4 >30 0.5 0.8 >30 1.7 0.7 27 >30 >30 >30 >30 >30 >30 >30 >30 8 4.3 >30 27 9.4 >30 >30 25.3 >30 96.5 2.7 0.12 0.13 >30 0.13 0.13 3.7 10 8.4 >30 6.2 25.2 >30 29.9 8.326.9 11 5 >30 1.4 3.1 >30 3.4 9.6 5.6 12 >30 >30 >30 >30 >30 >30 >30 >3013 11.1 >30 0.8 1.5 >30 3 2.3 9.6 14 >30 >30 >30 >30 >30 >30 >30 >30 162.65 16.14 2.22 2.78 5.6 9.80 5.45 5.29 18 12.70 6.43 2.12 1.59 6.2 7.285.54 1.14 19 2.34 2.30 0.34 0.21 0.3 8.62 4.84 0.32 20 3.25 0.96 0.850.26 1.0 8.5 4.21 0.19 21 3.02 0.7 0.42 0.64 0.6 5.67 2.66 0.35 22 2.421.22 0.62 0.45 1.6 12.6 8.87 0.67 24 >30 >30 0.2 0.3 >30 4.4 2.06 >30 323.56 2.06 1.42 0.95 2.2 25.29 11.77 1.21 33 2.38 0.43 0.34 0.39 0.5 5.293.71 0.1 34 2.07 1.38 1.07 0.63 1.5 3.77 1.7 0.47 35 5.79 2.37 1.03 0.774.2 9.89 4.25 1.06 36 NT 0.16 0.18 NT NT 0.2 0.24 NT 37 NT 0.21 0.530.44 NT 0.92 0.4 NT 38 NT >30 1.40 5.51 NT 23.12 2.60 NT 39 NT 0.52 0.730.49 NT 1.43 0.8 NT 40 NT >30 1.31 3.02 NT 14.11 1.91 NT NT = Not tested

TABLE 6 Assessment of a series of compounds for their ability to retardthe proliferation of a range of somatic cancer cells IC₅₀ (μM)Pancreatic Brain Ovarian Compound MiaPaCa-2 U87-MG A172 OVCAR-3 A2780SK-OV-3 2 0.05 0.05 0.127 0.063 0.06 0.106 6 NT 0.478 0.193 0.063 NT0.193 9 0.06 0.05 0.16 0.058 0.09 0.142 13 NT 0.513 0.388 0.171 NT 0.62136 0.17 0.22 NT NT 0.14 NT 37 0.52 0.38 NT NT 0.32 NT 39 0.58 0.49 NT NT0.61 NT Comp1 0.89 0.25 NT NT 0.21 NT Comp2 0.59 0.23 NT NT 0.37 NTComp3 >3    >3 NT NT >3    NT NT = Not tested

The data demonstrate that compound 2 exhibited potent anti-proliferativeactivity (IC₅₀=<1 μM) against cell lines representative of NSCLC (A549),TNBC (MDA-MB-231) and prostate cancer (DU-145). Compound 2 wasmoderately active against liver cancer cells (HepG2) (IC50=1.9 μM).

Compounds 6 and 9 also exhibit potent activity (IC₅₀=<1 μM) againstNSCLC (A549) and both prostate cancer cell lines (PC3 and DU-145),unlike compound 2 which was only active against DU-145. Compounds 6 and9 were also moderately active against MDA-MB-231 (IC₅₀<2 μM) and HepG2(IC₅₀<4 μM).

Using the same methodology the racemate of compound 2 and itsenantiomers were assessed against the A172 glioblastoma and OVCAR-3ovarian cancer cell lines. As was observed in the GBM explant studyabove, the eutomer of compound 2 was at least 2-fold more active againstboth cell lines when compared with the racemate (see FIG. 5). Thedistomer was >5 fold less active compared with the racemate (not shown).

Given the concept that residual cancer progenitor cells within thetumour post-treatment are responsible for tumour relapse, a criticaltherapeutic strategy to prolong survival is to eradicate those tumourprogenitor cells driving relapse. In vitro studies were conducted todetermine whether compound 2 was able to inhibit OCSC proliferation oncedrug pressure was removed. OCSC-2 cells were treated with 0.1, 1 and 10μg/ml of compound 2 for 24 hrs, washed with culture medium and allowedto recover for a further 50 hrs under standard incubation conditions.Culture plates were immediately placed in the Incucyte system and imagedevery 2 hrs. Growth curves were calculated as a measure of cellconfluence using an integrated confluence algorithm as a surrogate forcell number to determine proliferation rate.

In contrast to OCSC-2 cells treated with vehicle, those cells that werepre-treated with compound 2 for 24 hrs failed to enter logarithmicgrowth after an additional 48 hrs of culture in medium without drug (seeFIG. 6). Morphologically these cells appeared rounded and had apoptoticbodies suggesting that the cells were no longer viable from 24 hrsexposure (see FIG. 7).

Example 3 Cell Studies

GFP-labeled OCSC2 and mCherry-labeled OCC2 cells were established byinfecting cells with lentivirus expressing the fluorescent proteins(Craveiro et al. 2013). Co-cultures of GFP+OCSC2 and mCherry+OCC2 weretreated with 1 μg/ml of compound 2 for 48 hrs and allowed to recover foranother 72 hrs. Fluorescence was determined by fluorescence microscopy.Compound 2 markedly reduced GFP-labeled OCSC2 stem cell numbers andcaused mCherry-labeled OCC2 cells to round up and lift off the culturesurface (see FIG. 8). These data indicate that compound 2 disrupts theproliferation of both ovarian cancer stem cells and ovarian cancersomatic cells.

Ovarian cancer stem cell spheroids were obtained from cultures grownunder special conditions that selected for cells with self-renewingpotential (Alvero et al., 2009). Briefly, CD44+ cells were incubated ina suspension system consisting of a glass tube in continuous rotation toprevent adherence These cells formed clusters in 48 hrs and compactspheroids in 4 days. Spheroids were then exposed to 0.1 and 1 μg/ml ofcompound 2 and examined microscopically after 24 hrs. After 24 hrsexposure to compound 2 at 0.1 μg/ml the ovarian cancer spheroidsinfrastructure had started to disintegrate. At 1 μg/ml of compound 2 thespheroid structure was almost totally destroyed. These data demonstratethat compound 2 is able to penetrate the spheroid and destroy itsinfrastructure (see FIG. 9) and is suggestive that the compound shouldbe able to enter the tumour micro-environment.

REFERENCES

Craveiro, V., Yang-Hartwich, Y., Holmberg, J. C., Sumi, N. J., Pizzonia,J., Grffin, B., Gill., S. K., Sliasi, D-A., Azodi, M., Rutherford, T.,Alvero, A, B., Mor, G. (2013). “Phenotypic modifications in ovariancancer stem cells following Paclitaxel treatment” Cancer Medicine, 2(6),751-762.

Alvero A. B., Chen R, Fu H. H, Montagna M., Schwartz P. E., RutherfordT., Silasi D. A., Steffensen K. D., Waldstrom M., Visintin I., Mor G.(2009) “Molecular phenotyping of human ovarian cancer stem cellsunravels the mechanisms for repair and chemoresistance” Cell Cycle. 2009Jan. 1; 8(1):158-66.

Example 4 Pharmacokinetic Testing

A study of the pharmacokinetic behavior of compounds 2, 6, 9, 13 wasperformed. The results demonstrated that the compounds can be deliveredand achieve plasma concentrations with the proposed pharmaceutic windowof efficacy.

The study comprised Phase 1, a preformulation study ensuring allcompounds were soluble in 30% Captisol® solution and formed a homogenousmixture suitable for i.v delivery. A number of LC-MS methods weredeveloped and partially validated to ensure each analyte could bequantified from the plasma matrix and that there was no interferencebetween any of the analytes. Phase 2 comprised the in-life study wherebySprague-Dawley rats were acclimatised for three days prior to beinginjected in the tail vein with a cassette dose of four compounds, eachat a final concentration of 1 mg/Kg. A total of three rats were used inthe study with blood sampling with anticoagulant tubes at 5 mins, 30mins, 1 hr, 2 hrs, 4 hrs, 6 hrs and 8 hrs. The third phase of the studywas the bioanalysis of the analytes. The blood samples were centrifugedat 1200 rpm for 10 mins at 4° C. After the RBCs and the plasma wereseparated, the plasma was stored at −80° C. until processed and injectedinto the LC-MS. Samples from individual rats were treated as individualsamples with the PK profile generated from the mean of the data from thethree rats. The results are shown in FIG. 10.

Example 5 In Vivo Efficacy

Using the U87 flank model model previously described, suppositorydelivery of the eutomer of compound 9 at 100 mg/kg daily elicited astrong anti-tumour effect. The results are shown in FIG. 11. Two-wayANOVA with Sidak's correction for multiple comparisons indicated thattumour size was significantly smaller by just 7 days post-treatmentinitiation and this continued through to day 12 (the final time pointassessed). The rate of tumour growth was also significantly reduced bythe eutomer of compound 9. Tumour weight at end point was significantlyreduced by the eutomer of compound 9 compared to Captisol® control(unpaired t test, P=0.0036). Final mouse weights in the treatment andcontrol groups were not significantly different, however 3 mice in thetreatment group of an original 7 died (all animals that died were withinthe lower quartile of animal weight range). These mice also showedsignificant reduction in tumour growth, although, for consistency, thedata from those animals has been removed form all data presented andfrom statistical analysis. As with the previous dosing schedule, noovert clinical signs of toxicity (i.e. piloerection, morbidity,diarrhea) were noted. Histopathological analysis is ongoing to identifythe cause of death. Blood counts were normal.

Example 6 In Vivo Efficacy

The ovarian cancer animal model used to assess the in vivo efficacy ofcompound 2 consists of intraperitoneal injection of 7×10⁶ mCherry-CD44+ovarian cancer stem cells into athymic mice. In this model, tumorformation replicates the morphology of human ovarian cancer, giving riseto disseminated tumors comprising both CD44+ and CD44−OCC, confirmingthat the injected cancer stem cells can form heterogeneous tumors. Inthis rodent model, tumor progression is characterized by disseminatedcarcinomatosis where tumors are found in the ovaries, mesentery,peritoneum, diaphragm, liver, pancreas, and spleen. The model alsomimics the clinical profile for ovarian cancer and is characterized byan initial partial response to paclitaxel or cisplatin, which is thenfollowed by recurrence and resistance to the original therapy. Tumorprogression is monitored by life imaging using a Brukerfluorescence/X-Ray imaging system Vivo FX System (Bruker Corp.,Billerica, Mass.) (Craveiro et al. 2013).

Compared to control animals treated with 20% Captisol®, the eutomer ofCompound 2 dosed on a daily i.p. schedule formulated in a cyclodextrinelicited a significant, dose-dependent reduction in the rate of tumorproliferation (FIG. 12A) and terminal tumor burden (FIG. 12B). Weobserved a concentration-dependent response where animals dosed withcompound 2 at 50 mg/kg and 100 mg/kg had a 65% and >80% reduction intumor burden respectively compared with control.

Reference

Craveiro, V., Yang-Hartwich, Y., Holmberg, J. C., Sumi, N. J., Pizzonia,J., Grffin, B., Gill., S. K., Sliasi, D-A., Azodi, M., Rutherford, T.,Alvero, A, B., Mor, G. (2013). “Phenotypic modifications in ovariancancer stem cells following Paclitaxel treatment” Cancer Medicine, 2(6),751-762.

The citation of any reference herein should not be construed as anadmission that such reference is available as prior art to the presentapplication. Further, the reference in this specification to any priorpublication (or information derived from it), or to any matter which isknown, is not, and should not be taken as an acknowledgement oradmission or any form of suggestion that that prior publication (orinformation derived from it) or known matter forms part of the commongeneral knowledge in the field of endevour to which this specificationrelates.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is to be understood that the inventionincludes all such variations and modifications. The invention alsoincludes all of the steps, features, compositions and compounds referredto or indicated in this specification, individually or collectively, andany and all combinations of any two or more of said steps, features,compositions and compounds.

The invention is claimed as follows:
 1. A compound of the generalformula (I)

or a pharmaceutically acceptable salt, hydrate, derivative, solvate orprodrug thereof, wherein: R¹ is selected from the group consisting of: Hand C₁-C₆ alkyl, R² is selected from the group consisting of: OH andC₁-C₆ alkoxy, R³ is selected from the group consisting of: H, C₁-C₆alkyl and halo, R¹⁰ to R¹² are independently selected from the groupconsisting of: OH, C₁-C₆ alkyl, C₁-C₆ alkoxy and halo, R¹³ is selectedfrom the group consisting of: OH, C₁-C₆ alkoxy, NH₂, NHMe, NHEt, N(Me)₂and N(Et)₂, R¹⁴ and R¹⁵ are independently selected from the groupconsisting of: H, OH, C₁-C₆ alkyl and halo, or R¹³ and one of R¹⁴ andR¹⁵ form the following structure:


2. The compound of claim 1, wherein R¹ is selected from the groupconsisting of: H and C₁-C₃ alkyl.
 3. The compound of claim 1, wherein R²is OH.
 4. The compound of claim 1, wherein R³ is selected from the groupconsisting of: H, C₁-C₃ alkyl and halo.
 5. The compound of claim 1,wherein R¹⁰ is selected from the group consisting of: OH, OMe and halo.6. The compound of claim 1, wherein R¹⁰ is selected from the groupconsisting of: OH, OMe and F.
 7. The compound of claim 1, wherein R¹¹and R¹² are independently selected from the group consisting of: OH,OMe, C₁-C₄ alkyl and F.
 8. The compound of claim 1, wherein R¹¹ and R¹²are independently selected from the group consisting of: OMe,tert-butyl, and F.
 9. The compound of claim 1, wherein R¹³ is selectedfrom the group consisting of: OH, OMe, NH₂, NHEt and N(Et)₂.
 10. Thecompound of claim 1, wherein R¹⁴ and R¹⁵ are independently selected fromthe group consisting of: H, F, Cl and methyl.
 11. The compound of claim1, wherein R¹³ and one of R¹⁴ and R¹⁵ form the following structure:


12. A compound of formula (I) having the following structure:

wherein R¹, R³ and R¹⁰ to R¹⁵ are as defined in claim
 1. 13. A compoundof formula (I) selected from the group consisting of:


14. A pharmaceutical composition comprising the compound of formula (I)according to claim 1 and further comprising a pharmaceuticallyacceptable carrier, diluent or excipient.
 15. A method for the treatmentof cancer in a subject in need thereof, the method comprisingadministration to the subject of a therapeutically effective amount ofthe compound of formula (I) according to claim
 1. 16. The method ofclaim 15, wherein the cancer is a cancer that has recurred.
 17. Themethod of claim 15, wherein the cancer is resistant to one or morechemotherapeutic agents.
 18. The method of claim 15, wherein the canceris selected from the group consisting of: pancreatic cancer, colorectalcancer, melanoma, prostate cancer, brain cancer (including paediatricand adult), ovarian cancer, breast cancer, lung cancer, liver cancer,uterine cancer, neuroblastoma, mesothelioma, malignant ascites andperitoneal cancer.
 19. A method for reducing incidences of, or risk of,cancer recurrence in a subject deemed to be at risk of cancerrecurrence, the method comprising administration to the subject of aneffective amount of the compound of formula (I) according to claim 1.20. The method of claim 19, wherein the subject deemed to be at risk ofcancer recurrence is a subject who is in cancer remission.